Artificial Life is an interdisciplinary effort to investigate the fundamental properties of living systems through the simulation and synthesis of life-like processes in artificial media. The field brings a powerful set of tools to the study of how high-level behavior can arise in systems governed by simple rules of interaction. This tenth volume marks two decades of research in this interdisciplinary scientific comunity, a period marked by vast advances in the life sciences. The field has contributed fundamentally to our understanding of life itself through computer models, and has led to novel solutions to complex real-world problems -- from disease prevention to stock market prediction -- across high technology and human society. The proceedings of the biennial A-life conference -- which has grown over the years from a small workshop in Santa Fe to a major international meeting -- reflect the increasing importance of the work to all areas of contemporary science.