Noting that advertising agencies have not been examined as a collective industry, this paper looks at the development and structure of the advertising agency industry. The first portion of the paper discusses the development of the agency. The remaining two sections deal with trends in and the structure of the industry including: (1) the growth of independent services, (2) the rise of "in-house" agencies, (3) increased multinational expansion, (4) the acquisition and merger movement, (5) the movement away from the traditional compensation system, (6) the growth of market demand, (7) the ease of industry entry and survival, (8) industry concentration, and (9) product differentiation. (HTH)