From the reviews:
“Lattice theory has come a long way... For those who appreciate lattice theory, or who are curious about its techniques and intriguing internal problems, Professor Grätzer's lucid new book provides a most valuable guide to many recent developments. Even a cursory reading should provide those few who may still believe that lattice theory is superficial or naive, with convincing evidence of its technical depth and sophistication.” Garrett Birkhoff (Bulletin of the American Mathematical Society
“Grätzer’s book General Lattice Theory has become the lattice theorist’s bible.” (Mathematical Reviews)
“This book has a long history maturing in contents and details over a period of more than 40 years. ... For many years to come it will be the standard textbook and main reference for everybody interested in Lattice Theory. ... It contains more than 1,000 exercises, a bibliography of 742 items, and a useful glossary of notation. All this, together with the very clear style of presentation, makes the book an extremely valuable contribution to the theory of lattices.” (M. Mitsch, Monatshefte für Mathematik, Vol. 164 (4), 2011)
“This book is a new version of the author’s famous book on lattice theory, which appeared in several editions ... . The bibliography was updated and now contains 742 items. ... the integration of the former appendices into the main body of the book was a very good idea, as it will help the reader to get a clearer picture of the current state of the art in lattice theory.” (G. Eigenthaler, Zentralblatt MATH, Vol. 1233, 2012)