This book is an integrated exposition of the algebraic, and especially semigroup-theoretic, approach to machines and languages. Designed
to carry the reader from the elementary theory all the way to hitherto unpublished research results, it can be used as a text, as a reference
book for workers in the field, and as a chance for readers with an interest in any subset of {machines, languages, semigroups} to extend their interest to the whole set.