This book constitutes the refereed proceedings of the 6th International Conference on Evolutionary Programming, EP 97, held in Indianapolis, IN, USA, in April 1997. The 36 revised full papers presented were carefully selected for inclusion in the proceedings. The papers are organized in sections on evolutionary methods for modeling and training, alternative frameworks for the computational study of evolutionary social systems, genetic programming: issues and applications, issues in evolutionary optimization, enhanced evolutionary operators, theory and analysis of evolutionary computations, issues in adaptability: theory and practice, and evolution and NP-hard problems.