Most of this book will deal§with optimal one-sided search. In a one-sided search, the target can move but§it does not react to the search. Optimal§Search is simply the search for the best path to a specific goal, no matter§what the goal is. It can be finding a missing airliner or ship, a survivalist§suspected in the death of a police officer, the shortest route between several§points (the Traveling Salesman Problem, e.g.), or the solution to inventory§replenishment. The final chapter will present an overview of optimal§two-sided search. In this type of search, the target can react to the searcher.§It may react in a way to avoid detection, or it may try to "cooperate" with the§searcher in attempting to be found by or to rendezvous with the searcher.§§This book is a sequel to the Theory§of Optimal Search (TOS) which was first published in 1975. TOS dealt extensively§with the stationary target problem, but contained few results for moving targets. This reflected§the state of knowledge at the time the book was published. Starting in the late 1970s, work by Brown, Washburn, and§Stone produced a remarkably complete theory for finding optimal one-sided§search plans. As well as characterizing optimal plans, the theory yielded§methods for computing optimal search plans that are easily implemented on§present day computers.§§