The research reported here represents the first year of a three-year effort to gain a better understanding of the processes that contribute to Team Evolution and Maturation (TEAM) in operational Navy contexts. The ultimate objective of this research is to provide a basis for enhancing the training, performance, and unit maintenance functions of Navy teams. The general focus of this effort is to measure team evolution and maturation as team members gain experience and knowledge about tasks, each other, and external environmental demands within the context of an operational training scenario. Existing models and methodologies have been synthesized from the team-performance-team-training literatures as a basis for the development of a working model of team evolution and maturation. Based on this model, prototype procedures and methods for measuring team development have been defined and developed. These measurement technologies have been tested at the Naval Gunfire Support Department (NGFS) at the Naval Amphibious School, Little Creek. Results of this effort indicate that the developing concepts, methods, and procedures are viable tools for the study of team training and performance. The results support the proposed stage model of team development and provide a sound foundation for the development of interventions for the enhancement of team training.