Optimieren Sie Ihre Suche

  • Bücher (1.181)

bis

Benutzerdefinierte Preisspanne (EUR)

bis

R hicks (Mehr als 1.100 Ergebnisse)

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2019

    1328635171 / 9781328635174

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 3,97

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 20 verfügbar

    Paperback. Zustand: Very Good. As the stakes continue to rise, the boy must piece together the disjointed clues of his origins while using his limited knowledge to stop one of the greatest art frauds ever attempted. Digitally interactive, this breathtaking museum mystery offers QR codes woven throughout the book that bring renowned paintings to readers fingertips.…

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2019

    1328635171 / 9781328635174

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 3,97

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: Mehr als 20 verfügbar

    Paperback. Zustand: Good. As the stakes continue to rise, the boy must piece together the disjointed clues of his origins while using his limited knowledge to stop one of the greatest art frauds ever attempted. Digitally interactive, this breathtaking museum mystery offers QR codes woven throughout the book that bring renowned paintings to readers fingertips.…

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2019

    1328635171 / 9781328635174

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 3,97

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 4 verfügbar

    Paperback. Zustand: Fair. As the stakes continue to rise, the boy must piece together the disjointed clues of his origins while using his limited knowledge to stop one of the greatest art frauds ever attempted. Digitally interactive, this breathtaking museum mystery offers QR codes woven throughout the book that bring renowned paintings to readers fingertips.…

  • Sprache: Englisch

    Verlag: Struik Christian Books, 2001

    0892740027 / 9780892740024

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 3,98

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Zustand: Very Good.

  • Sprache: Englisch

    Verlag: Clarion Books, 2013

    0544105044 / 9780544105041

    Serie: Buch 1 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,06

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. Twelve-year-old Colophon Letterford has a serious mystery on her hands. Will she discover the link between her family's literary legacy and Shakespeare's tomb before it's too late? Antique paintings, secret passages, locked mausoleums, a four-hundred-year-old treasure, and a cast of quirky (and some ignoble) characters all add up to a fun original adventure. Readers will revel in a whirlwind journey through literary time and space in real-world locales from Mont St. Michel to Stratford-Upon-Avon to Central Park. Geyer, Mark Edward (illustrator). …

  • Sprache: Englisch

    Verlag: Clarion Books, 2013

    0544105044 / 9780544105041

    Serie: Buch 1 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 4,06

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 14 verfügbar

    Paperback. Zustand: Good. Twelve-year-old Colophon Letterford has a serious mystery on her hands. Will she discover the link between her family's literary legacy and Shakespeare's tomb before it's too late? Antique paintings, secret passages, locked mausoleums, a four-hundred-year-old treasure, and a cast of quirky (and some ignoble) characters all add up to a fun original adventure. Readers will revel in a whirlwind journey through literary time and space in real-world locales from Mont St. Michel to Stratford-Upon-Avon to Central Park. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Clarion Books, 2013

    0544105044 / 9780544105041

    Serie: Buch 1 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,06

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 4 verfügbar

    Paperback. Zustand: Fair. Twelve-year-old Colophon Letterford has a serious mystery on her hands. Will she discover the link between her family's literary legacy and Shakespeare's tomb before it's too late? Antique paintings, secret passages, locked mausoleums, a four-hundred-year-old treasure, and a cast of quirky (and some ignoble) characters all add up to a fun original adventure. Readers will revel in a whirlwind journey through literary time and space in real-world locales from Mont St. Michel to Stratford-Upon-Avon to Central Park. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: WW Norton & Co, 1997

    0393972143 / 9780393972146

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,22

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 3 verfügbar

    Paperback. Zustand: Fair. Selections are organized around ten broad themes, including education, science, abortion, the causes of crimes, and the existence of God. An alternative table of contents classifies selections by logical genre and the use of techniques such as generalization, analogy, statistical reasoning, and explanation. Study questions at the end of each reading help to focus student analysis. …

  • Sprache: Englisch

    Verlag: WW Norton & Co, 1997

    0393972143 / 9780393972146

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,22

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. Selections are organized around ten broad themes, including education, science, abortion, the causes of crimes, and the existence of God. An alternative table of contents classifies selections by logical genre and the use of techniques such as generalization, analogy, statistical reasoning, and explanation. Study questions at the end of each reading help to focus student analysis. …

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2021

    0358569761 / 9780358569763

    Serie: Buch 2 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,31

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. In this standalone companion to The Van Gogh Deception, Art and Camille team up once again to solve a large museum theft, using one of the biggest heists in history to help them solve the case.

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2021

    0358569761 / 9780358569763

    Serie: Buch 2 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 4,31

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 5 verfügbar

    Paperback. Zustand: Good. In this standalone companion to The Van Gogh Deception, Art and Camille team up once again to solve a large museum theft, using one of the biggest heists in history to help them solve the case.

  • Sprache: Englisch

    Verlag: James Hicks (edition ), 2012

    0615701671 / 9780615701677

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,31

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 2 verfügbar

    Paperback. Zustand: Very Good. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting. Hicks, D. Jason (illustrator).

  • Sprache: Englisch

    Verlag: Clarion Books (edition Reprint), 2021

    0358569761 / 9780358569763

    Serie: Buch 2 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,32

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. Reprint. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting.

  • Sprache: Englisch

    Verlag: Clarion Books, 2014

    0544336305 / 9780544336308

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,49

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 3 verfügbar

    Paperback. Zustand: Very Good. Colophon Letterford's life changed overnight when she uncovered Shakespeare's lost manuscripts. Now the authenticity of those manuscripts is in question and the family publishing business is in danger. In this exciting mystery, thirteen-year-old Colophon travels from Oxford's lofty Tower of the Five Orders to the dank depths of London's sewers in her pursuit of truth and honor. But the stakes are high. Budding cryptologists, Shakespeare fans, and mystery lovers alike will revel in the twists and turns of this fascinating middle grade sequel to Secrets of Shakespeare's Grave. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Clarion Books, 2014

    0544336305 / 9780544336308

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 4,49

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 2 verfügbar

    Paperback. Zustand: Good. Colophon Letterford's life changed overnight when she uncovered Shakespeare's lost manuscripts. Now the authenticity of those manuscripts is in question and the family publishing business is in danger. In this exciting mystery, thirteen-year-old Colophon travels from Oxford's lofty Tower of the Five Orders to the dank depths of London's sewers in her pursuit of truth and honor. But the stakes are high. Budding cryptologists, Shakespeare fans, and mystery lovers alike will revel in the twists and turns of this fascinating middle grade sequel to Secrets of Shakespeare's Grave. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Clarion Books, 2014

    0544336305 / 9780544336308

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,49

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 3 verfügbar

    Paperback. Zustand: Fair. Colophon Letterford's life changed overnight when she uncovered Shakespeare's lost manuscripts. Now the authenticity of those manuscripts is in question and the family publishing business is in danger. In this exciting mystery, thirteen-year-old Colophon travels from Oxford's lofty Tower of the Five Orders to the dank depths of London's sewers in her pursuit of truth and honor. But the stakes are high. Budding cryptologists, Shakespeare fans, and mystery lovers alike will revel in the twists and turns of this fascinating middle grade sequel to Secrets of Shakespeare's Grave. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Clarion Books (edition Reprint), 2021

    0358569761 / 9780358569763

    Serie: Buch 2 von 3 - The Lost Art Mysteries

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,53

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Fair. Reprint. The item might be beaten up but readable. May contain markings or highlighting, as well as stains, bent corners, or any other major defect, but the text is not obscured in any way.

  • Sprache: Englisch

    Verlag: Non-Subscriber, 1982

    0892742461 / 9780892742462

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,58

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Fair.

  • Sprache: Englisch

    Verlag: Non-Subscriber, 1982

    0892742461 / 9780892742462

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 4,58

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Good.

  • Sprache: Englisch

    Verlag: Clarion Books (edition Reprint), 2014

    0544336305 / 9780544336308

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 4,73

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 2 verfügbar

    Paperback. Zustand: Very Good. Reprint. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting. Geyer, Mark Edward (illustrator).

  • Sprache: Englisch

    Verlag: Clarion Books, 2017

    0544759273 / 9780544759275

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Hardcover

    Anbieter: Dream Books Co., Denver, CO, USADream Books Co.

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 4,81

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Zustand: acceptable. This copy has clearly been enjoyedâ"expect noticeable shelf wear and some minor creases to the cover. Binding is strong, and all pages are legible. May contain previous library markings or stamps.

  • Sprache: Englisch

    Verlag: CreateSpace Independent Publishing Platform (edition 2), 2015

    1502845768 / 9781502845764

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 5,13

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 2 verfügbar

    Paperback. Zustand: Very Good. 2. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting.

  • Sprache: Englisch

    Verlag: Houghton Mifflin, 2013

    0547839537 / 9780547839530

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Hardcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 5,35

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Hardback. Zustand: Good. Colophon Letterford s life changed overnight when she uncovered Shakespeare s lost manuscripts. Now the authenticity of those manuscripts is in question and the family publishing business is in danger. In this exciting mystery, thirteen-year-old Colophon travels from Oxford s lofty Tower of the Five Orders to the dank depths of London s sewers in her pursuit of truth and honor. But the stakes are high. Budding cryptologists, Shakespeare fans, and mystery lovers alike will revel in the twists and turns of this fascinating middle grade sequel to Secrets of Shakespeare s Grave. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Houghton Mifflin, 2013

    0547839537 / 9780547839530

    Serie: Buch 2 von 2 - The Shakespeare Mysteries

    • Hardcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 5,35

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Hardback. Zustand: Very Good. Colophon Letterford s life changed overnight when she uncovered Shakespeare s lost manuscripts. Now the authenticity of those manuscripts is in question and the family publishing business is in danger. In this exciting mystery, thirteen-year-old Colophon travels from Oxford s lofty Tower of the Five Orders to the dank depths of London s sewers in her pursuit of truth and honor. But the stakes are high. Budding cryptologists, Shakespeare fans, and mystery lovers alike will revel in the twists and turns of this fascinating middle grade sequel to Secrets of Shakespeare s Grave. Geyer, Mark Edward (illustrator).…

  • Sprache: Englisch

    Verlag: Clarion Books (edition ), 2017

    0544759273 / 9780544759275

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Hardcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 5,45

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Hardcover. Zustand: Fair. With dust jacket. The item might be beaten up but readable. May contain markings or highlighting, as well as stains, bent corners, or any other major defect, but the text is not obscured in any way.

  • Sprache: Englisch

    Verlag: HarperCollins Publishers Inc, 2021

    0358396069 / 9780358396062

    Serie: Buch 3 von 3 - The Lost Art Mysteries

    • Hardcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Befriedigend

    EUR 5,47

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 5 verfügbar

    Hardback. Zustand: Good. In another suspenseful mystery romp with art appreciation (Kirkus Reviews, starred review), Art and Camille head to London to find her estranged father, and soon find themselves embroiled in a heist involving a long-dead monarch.

  • Sprache: Englisch

    Verlag: Clarion Books (edition ), 2017

    0544759273 / 9780544759275

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Hardcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 5,59

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Hardcover. Zustand: Very Good. With dust jacket. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting.

  • Sprache: Englisch

    Verlag: Clarion Books (edition ), 2017

    0544759273 / 9780544759275

    Serie: Buch 1 von 3 - The Lost Art Mysteries

    • Hardcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Ausreichend

    EUR 5,83

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Hardcover. Zustand: Fair. With dust jacket. The item might be beaten up but readable. May contain markings or highlighting, as well as stains, bent corners, or any other major defect, but the text is not obscured in any way. Ex-Library.

  • Sprache: Englisch

    Verlag: Clarion Books (edition Illustrated), 2013

    0544105044 / 9780544105041

    Serie: Buch 1 von 2 - The Shakespeare Mysteries

    • Softcover

    Anbieter: BooksRun, Philadelphia, PA, USABooksRun

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 5,89

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. Illustrated. It's a well-cared-for item that has seen limited use. The item may show minor signs of wear. All the text is legible, with all pages included. It may have slight markings and/or highlighting. Geyer, Mark Edward (illustrator).

  • Sprache: Englisch

    Verlag: Oxford University Press, 1975

    0198282699 / 9780198282693

    • Softcover

    Anbieter: World of Books (was SecondSale), Montgomery, IL, USAWorld of Books (was SecondSale)

    Verkäufer/-in mit 5 Sternen
    Verkäufer/-in kontaktieren

    Zustand: Gebraucht - Gut

    EUR 5,94

     Versand gratis 
    Versand innerhalb von USA

    Anzahl: 1 verfügbar

    Paperback. Zustand: Very Good. Value and Capital An Inquiry into some Fundamental Principles of Economic Theory.