* Contains over 100 exercises * "Do-it-yourself" instructions included for theorems * An elementary approach to partial differential equations presented, with minimal prerequisites * Self-contained chapters, split into two main parts Serge Alinhac (1948 the second describes the wave equation and its perturbations for two- or three-space dimensions. Over 100 exercises are included, as well as "do it yourself" instructions for the proofs of many theorems. Only an understanding of differential calculus is required. Notes at the end of the self-contained chapters, as well as references at the end of the book, enable ease-of-use for both the student and the independent researcher.