This book was written for first and second year undergraduates in electronic engineering and the physical sciences with the aim of providing a firm grounding in the study of signals and systems. In this second edition the authors provide a more detailed treatment of the z-transform. A new chapter serves to review and integrate much of the earlier material, while introducing the discrete Fourier transform in the context of signal capture and spectral analysis. These changes reflect the growing important of discrete-time topics in undergraduate studies and the fact that many students now have direct experience in the use and application of signal-processing software. Emphasis is placed on discussion rather than on detailed mathematical proofs, with the aim of developing and encouraging a critical approach to the use of software tools.