This book constitutes the refereed proceedings of the 18th International Symposium on Algorithms and Computation, ISAAC 2007, held in Sendai, Japan, in December 2007.

The 77 revised full papers presented together with 2 invited talks were carefully reviewed and selected from 220 submissions. The papers are organized in topical sections on graph algorithms, computational geometry, complexity, graph drawing, distributed algorithms, optimization, data structure, game theory, database applications, online algorithms, I/O algorithms, networks, geometric applications, and string.