"The book presents the formal machinery of LDSs (Labelled deductive systems): proof theory, semantics, and algebraic LDSs, with many examples: modal and tense logics, fuzzy and many-valued logics, linear and relevant logics, nonmonotonic logic, etc. . . .this book will be of great interest for anyone who wants to grasp, together with a number of formal techniques, a multiplicity of logical systems, mostly related to computer science and artificial intelligence." --Mathematical Reviews