Joseph Carnahan and Rahul Simha IEEE Potentials Volume 20, Issue 2, pp. 21-24 April 2001 Combinatorial optimization problems typically require every possible solution to be evaluated to ensure finding the optimal solution. Since such exhaustive searches are often impractical, there is now a vast body of heuristic algorithms for them. Among the algorithms are those based on metaphors borrowed from other areas of science. The idea is that key elements of physical processes can be used abstractly to form the basis of an optimization algorithm. This article presents a broad overview of several metaphor-based algorithms, including the widely-used genetic and simulated annealing algorithms. genetic algorithms, simulated annealing, travelling salesman problems, genetic algorithms, combinatorial optimization problems, optimal solution, heuristic algorithms, physical processes, optimization algorithm, metaphor-based algorithms, simulated annealing algorithms