A computer program to solve a problem by search has to follow steps analogous to those we take when we look for a lost object. Essentially, it has to decide where to look or what to ask next, it has to remember what it has found out, and it has to recognize the solution when it finds it. The examples that follow should be enough for you to understand the basics of computer search. For a fuller account you could look at Charniak and McDermott (1985) or Rich (1983).
We will begin with our Automated Tourist Guide project, and show how a helpful terminal at a London Underground station could find the best route to any other station. The second example will be used to show how similar strategies can be applied in apparently diverse ways, taking as an example the task of solving a type of jigsaw puzzle. We will also briefly mention the relationship of search to playing games, where an adversary is continuously trying to make the problem as hard as possible.