I first learned about them from a digital logic perspective, so they were already very practical tools for me when I ran into them in my theory classes. One of

I first learned about them from a digital logic perspective, so they were already very practical tools for me when I ran into them in my theory classes. One of the best free resources I can find in short order is the wiki article on them. http://en.wikipedia.org/wiki/Finite-state_machine http://en.wikipedia.org/wiki/Finite-state_machine The wiki page on deterministic finite automata would be useful to see the CS theory/language side of the idea. http://en.wikipedia.org/wiki/Deterministic_finite_automaton http://en.wikipedia.org/wiki/Deterministic_finite_automaton