From the reviews:

"The book under review represents a fundamental monograph on the theory of L^{2}-invariants. … To a great extent, it is self-contained. … The book is very clearly written, it contains many examples and we can find exercises at the end of each chapter. … At many places in the book, the reader will find hints for further research. … The book will be of great interest to specialists but it can also be strongly recommended for postgraduate students." (EMS Newsletter, March, 2005)

"L^{2}-invariants were introduced into topology by Atiyah in 1976 … . Since then, the theory has been developed successfully by many researchers, among them the author of this monograph … . This book is an excellent survey of many up-to-date results … . It could be used as a very good introduction to the subject of L^{2}-invariants … usable either for self-study or as a text for a graduate course. … Lück’s book will become the primary reference about L^{2}-variants for the foreseeable future." (Thomas Schick, Mathematical Reviews, 2003 m)

"L^{2}-invariants were introduced into topology by Atiyah in the 1970’s … . The present book is the first substantial monograph on this topic. … This is an impressive account of much of what is presently known about these invariants … . It combines features of a text and a reference work; to a considerable degree the chapters can be read independently, and there are numerous nontrivial exercises, with nearly 50 pages of detailed hints at the end." (Jonathan A. Hillman, Zentralblatt MATH, Vol. 1009, 2003)