This well-acclaimed book, now in its twentieth edition, continues to offer an in-depth presentation of the fundamental concepts and their applications of ordinary and partial differential equations providing systematic solution techniques. The book provides step-by-step proofs of theorems to enhance students' problem-solving skill and includes plenty of carefully chosen solved examples to illustrate the concepts discussed. Designed as a textbook for undergraduate and postgraduate students of Mathematics and Physics as well as undergraduate students of all branches of Engineering and AMIE, this book would also be useful for the aspirants of GATE, CSIR-UGC (NET) and other competitive examinations