The computational molecular sciences utilize the techniques of rigorous chemical as well as physical theories and computer-based modeling, relying on specialized hardware and software development, algorithm design, and database management to examine and elucidate all aspects of the molecular sciences. These approaches bridge chemistry, biology, and the materials sciences and have connections to neighboring chemical as well as biological application-driven fields. WIREs Computational Molecular Science will review and highlight research from all these fields.. The award-winning WIREs (Wiley Interdisciplinary Reviews) series combines some of the most powerful features of encyclopedic reference works and review journals in an innovative online format. They are designed to promote a cross-disciplinary research ethos while maintaining the highest scientific and presentational standards, but should be viewed first and foremost as evolving online databases of cutting-edge reviews.