This monograph proposes and describes a systems-based field of study for the training and development (T&D) profession: human performance technology. The first section describes what is meant by a field of study and professional practice and then provides a rationale for the proposal. Section 2 explores training and development in the context of the growth of a new professional specialization. Section 3 presents an overview and description of human performance technology and then proposes a formal goal and definition of the field. In section 4, implications are set forth that should have relevance in two areas related to T&D: professional practice and academic programs. The final section presents 11 propositions that encapsulate the general characteristics of the field. These propositions illustrate that the uniqueness of the T&D profession lies in its role of helping people improve their performance using all aspects of the work environment and systems to make these improvements occur. Conclusions and a 74-item reference list are included. (SK)