The book is based on the notes from the graduate course given by the author at Rutgers University in the fall of 1994 and the spring of 1995. The main goal of the book is to acquaint the reader with various perspectives of the theory of automorphic forms. In addition to detailed and often nonstandard exposition of familiar topics of the theory, particular attention is paid to such subjects as thetafunctions and representations by quadratic forms. Readership Graduate students and research mathematicians working in number theory and related topics of algebraic geometry. Reviews "The author discusses many important topics in the theory of automorphic forms which are rarely seen in the textbooks available on the subject ... the presentation of the proofs ... is ... unusual, and this may give the reader a different flavor of the subject ... graduate students will certainly benefit from this book."  Mathematical Reviews "An excellent place to begin the study of the analytic approach to modular forms ... a welcome addition to this growing expository of literature."  Bulletin of the AMS "[T]his is an excellent book, requiring hard work from the reader and giving rich reward for her or his effort."  Zentralblatt MATH "An excellent graduate text. The book by Iwaniec provides the graduate student and the researcher wishing to acquire the basics on automorphic forms with a beautifully written and selfcontained treatment of the classical modular and automorphic forms, Kloosterman sums, Hecke operators, automorphic Lfunctions, cusp forms and Eisenstein series, spherical functions, theta functions and convolution Lfunctions."  Bulletin of the London Mathematical Society Table of Contents  Introduction
 The classical modular forms
 Automorphic forms in general
 The Eisenstein and the Poincaré series
 Kloosterman sums
 Bounds for the Fourier coefficients of cusp forms
 Hecke operators
 Automorphic \(L\)functions
 Cusp forms associated with elliptic curves
 Spherical functions
 Theta functions
 Representations by quadratic forms
 Automorphic forms associated with number fields
 Convolution \(L\)functions
 Index
