► Chapter 3 introduced state space search and demonstrated its origins in graph theory. ► Chapter 3 also introduced the finite state machine and showed how it could be used to generate a path through graphs. In ► Chap. 4 , we present more opportunities for state space search and demonstrate algorithms for exploring state space graphs. These general search algorithms are used when the path to the goal state for a problem, the solution path, is not known before the search begins.