This textbook is designed for an introductory, one-semester course in Signals and Systems for undergraduates. It is written to be concise, clear, and yet comprehensive to make it easier for the students to learn this important subject with high mathematical complexity. The popular MATLAB® software package is used for programming and simulation. Every new concept is explained with figures and examples for a clear understanding. The simple and clear style of presentation, along with comprehensive coverage, enables students to obtain a solid foundation in the subject and for use in practical applications.