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 & Signals 3e, 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.
Lathi's writing is extremely clear and, at times, funny. I loved some of the historical background he added, especially concerning Heaviside. He begins with a very helpful review of partial fraction expansion and linear algebra, two mathematical domains one needs to be facile in to absorb the remainder of the book. The book then covers a lot of ground. One could look at the book as divided into two major sections: I-Continuous-Time (Chapters 1-7) signals and systems, development of continuous Fourier/Laplace, sampling, analog filters (pole-zero placement, Butterworth, Chebyshev, etc.), and control systems. II-Discrete-Time (Chapters 8-13) Fourier, z-transform, digital filters, and space-state analysis). It's a wonderful resource for developing a mental throughline for the relationship between signals/systems, digital signal processing, and controls.