Written by an author who was at the forefront of developments in multivariable spectral theory during the seventies and the eighties, this book describes the spectral mapping theorem in various settings. In this second edition, the has been revised and expanded, whilst preserving the engaging style of the first.Starting with a summary of the basic algebraic systems – semigroups, rings and linear algebras – the book quickly turns to topological-algebraic systems, including Banach algebras, to set up the basic language of algebra and analysis. Key aspects of spectral theory are covered, in one and several variables. Finally the case of an arbitrary set of variables is discussed.  is an accessible and easy-to-read guide, providing a convenient overview of the topic to both students and researchers. "I certainly plan to add it to my own mathematical library" — Anthony Wickstead in the Irish Mathematical Society Bulletin"An excellent read" — Milena Stanislavova in the Mathematical Reviews"[Offers] a fresh perspective even for experts [...] Recommended" — David Feldman in Choiceweiterlesen