This book written with a view to impart informations regarding waves and oscillations is unimpeachable within the scope it professes to limit itself. The special features are that the physical implications of a theory has been particularly stressed and a brief resume of the recent developments have been given to provoke further interest in the students. The general theory, so developed, is applied to different fields to elaborate the subject matter. In this revised and enlarged edition many important topics, university questions and sceintific tables have been introduced so to meet the requirements of the students appearing in B.Sc. (Pass, Hons., Subsidiary), B. Tech., Bio-Eng., IAS, PCS, PMT, CPMT, JEE and in other competitive examinations. This book also provides various types of information related to waves to those students who have to appear before interview boards for the para-scientific posts in Air Force, Navy, Meteorological Laboratories and other Government organisations.