An easily comprehensible text for required undergraduate courses in computer theory. The book thoroughly covers the three fundamental areas of computer theory - formal languages, automata theory, and Turing machines, and attempts to remove the unnecessary mathematical complications associated with the study of these subjects. The author substitutes graphic representation for symbolic proofs, allowing students with poor mathematical background easily to follow each step. Included are a large selection of well thought out problems at the end of each chapter. A teacher's manual is available.