Theories of structure and agency attempt to answer the question of action: How is it that I can do what I want with others when their goals are different, and often incompatible with mine? Early theories relied on a conception of free will. Recent work has accepted that agency is a matter of social organization, not of the ultimate causes of motivation. What motivates a person to act in a particular way is not as important as how the action was accomplished, what contextual factors led up to it and what followed it.
Talcott Parsons was a primary figure in action theory in sociology in the 1950s. His work has fallen out of favor after being criticized as tautological and value-laden.
Anthony Giddens gave shape to the structure and agency debate with his 'Constitution of Society'.