This second edition contains much of the content of Linear Systems and Signals, Third Edition, by the same authors, with added chapters on analog and digital filters and digital signal processing, plus additional applications to communications and controls. Unlike Linear Systems and Signals, Third Edition, in this book the Laplace transform follows Fourier. This book contains enough material on discrete-time systems to be used in a traditional course in Signals and Systems and in an introductory course in Digital Signal Processing.