"The main merit of this work is the utmost clearness through which the author explains some subjects connected with very strong technical difficulties... The particular way used...to introduce the basic aspects of linking methods will be very encouraging and stimulating for young researchers... The book may be warmly recommended to all specialists in this fascinating field of current interest and growing importance."
--ZAA
"The book is addressed to mathematicians and students interested in critical points in any context...recommended also for researchers in the fields of pdes and nonlinear analysis... This reviewer calls the attention of the designers of algorithms for determining critical points to this book as a possible theoretical basis for new powerful numerical methods."
--Acta Sci. Math