Foundations of Computation is a free textbook for a one-semester course in theoretical computer science. It has been used for several years in a course at Hobart and William Smith Colleges. The course has no prerequisites other than introductory computer programming. The first half of the course covers material on logic/ sets/ and functions that would often be taught in a course in discrete mathematics. The second part covers material on automata/ formal languages/ and grammar that would ordinarily be encountered in an upper level course in theoretical computer science.