<p>From the reviews:</p><p>“Brezis has intelligently chosen several fundamental concepts of functional analysis, and has build the book around them and their applications. … for a newcomer who intends to become a user of functional analysis this book is an ideal place to start. In fact I would recommend this over any other source to any beginning graduate student. … the book also has all the basic tools for a beginer PDE researcher … . Its a bible for the field of research.” (Philosophy, Religion and Science Book Reviews, bookinspections.wordpress.com, October, 2013)</p><p>“This textbook has its origin in the French version Analyse fonctionnelle published in 1985, which has become a standard reference and was translated into several languages. … At the end of each chapter the reader will find comments with further information, references, and historic remarks. … In summary, the present textbook provides an excellent basis for a course on functional analysis plus a follow-up course on partial differential equations. It is well-written and I can wholeheartedly recommend it to both students and teachers.” (G. Teschl, Monatshefte für Mathematik, Vol. 165 (3-4), March, 2012)</p><p>“This book is a tour de force by the author, who is a master of modern nonlinear functional analysis and who has contributed extensively to the development of the theory of partial differential equations. … The writing is lively, the material is diverse and maintains a strong unity. … the book is a very useful contribution to the growing literature on this circle of ideas. I wholeheartedly recommend this book both as a textbook, as well as for independent study.” (Vicenţiu Rădulescu, Mathematical Reviews, Issue 2012 a)</p><p>“The book is the English translation of an 1983 book published in French: Analyse fonctionnelle :théorie et applications … . It has seen translations into numerous languages and the Springer edition was especially anticipated, as it announced a number of practice exercisesfollowing each chapter. I can honestly say that it was well worth the wait. … The text is a pleasure to read. … I wholeheartedly recommend this book as both a textbook as well as for independent study.” (Florin Catrina, The Mathematical Association of America, June, 2011)</p>