The second edition of this well-known and highly regarded text can be used as the basis for a one- or two-semester undergraduate course in signals and linear systems theory and applications. Topics include basic signals and systems concepts, linear time-invariant (LTI) systems, Fourier representations of continuous-time and discrete-time signals, the CT and DT Fourier transforms, and time- and frequency-domain analysis methods. The author emphasizes applications of the theory through numerous examples in filtering, sampling, communications, and feedback. The parallel development of continuous-time and discrete-time frequency domain methods allows the reader to apply insights and intuition across the two domains. It also facilitates a deeper understanding of the material by bringing into focus the similarities and differences between the two domains. The text also includes introductory chapters on communication systems and control theory. This book assumes that you have a background in calculus as well as exposure to complex numbers and elementary differential equations. Because of its thoroughness and unhurried pace, this text is highly recommended for students and those interested in self-study.