The material of the book is developed during teaching senior undergraduate and postgraduate students of the Indian Institute of Technology, Kharagpur. Two aspects ?Vibration of Mechanical Systems? and ?Structural Dynamics?, have been presented in a unified and integrated manner. Treating it as an introductory text on vibration and dynamics of structures, the reader is acquainted gradually to more advanced topics. The book will be useful to the research scholars and professional engineers, besides graduate students. Many example problems are presented to explain the text and a few computer programs presented may be of utility to the readers.