Description:This book constitutes the refereed proceedings of the 6th Scandinavian Workshop on Algorithm Theory, SWAT'98, held in Stockholm, Sweden, in July 1998.The volume presents 28 revised full papers selected from 56 submissions; also included are three invited contributions. The papers present original research on algorithms and data structures in various areas including computational geometry, parallel and distributed systems, graph theory, approximation, computational biology, queueing, Voronoi diagrams, and combinatorics in general.