This text is offered as a medical legal resource of the physician assistant profession. It is intended for use through all phases of the professional development of the physician assistant, from the high school student sorting through options in career choices, to physician assistant students, practicing physician assistants and supervisory physicians, or those who are considering practicing with a physician assistant. The history and development of the profession is reviewed, allowing an understanding of the role the physician assistant plays in the healthcare team approach to patient care. The scope of practice is defined, along with the key collaboration between the physician assistant and the supervising physician. Regulatory requirements are delineated by state, including basic requirements and maintenance of licensure and certification.