Computation models and specification methods seem to be worlds apart. The project on abstract state machines (a.k.a. evolving algebras) started as an attempt to bridge the gap by improving on Turing’s thesis [Evolving Algebras: An Introductory Tutorial]. We sought more versatile machines which would be able to simulate arbitrary algorithms, on their natural abstraction levels, in a direct and essentially coding-free way. The ASM thesis asserts that ASMs are such versatile machines. The guide provided the definition of sequential and — for the first time — parallel and distributed ASMs. The denotational semantics of sequential and parallel ASMs is addressed in the Michigan guide May 1997 Draft of the ASM Guide.