This text is an extensive revision of the author's highly successful text, "Linear Systems Theory and Design". In the third edition, the author is revising his formerly more theoretical approach to the topic of linear systems, choosing instead a more general approach that will appeal to a wider audience. A key feature of the revision is the incorporation of MATLAB throughout the text, with an emphasis on the ideas behind the computation and the interpretation of the results. The user-friendly approach to linear systems strikes a balance between theory and applications. The text is intended for undergraduate students of linear systems and multivariable system design.