The pharmaceutical industry plays a vital role in the world's economy, as well as in ensuring the welfare of its citizens. In the United States, this industry constitutes a large and important part of the economy. In 2002, health care expenditure in the United States reached $1.6 trillion, accounting for fifteen percent of total GNP. This percentage is also growing over time-it was seven percent in 1970. An important component of the health care industry is the pharmaceutical industry-in 2002, its size was estimated at $193 billion. While the pharmaceutical industry is driven by innovation, it spends more money on marketing than on research and development. For example, this industry spends more than any other U.S. industry on its sales ,force ($7 billion annually) and on media advertising ($2.8 billion annually).

Pharmaceutical companies typically direct their marketing efforts toward physicians and, as of late, directly to patients (consumers). The marketing efforts directed at physicians comprise personal selling through sales representatives (detailing); sampling (provision of drugs at no cost); physician meetings and events; and advertisements in medical journals. Since 1997, a change in the legal environment that allowed direct-to-consumer advertising (DTCA) has resulted in a 350% increase in expenditures for such advertising between 1996 and 2001. However, the biggest chunk of marketing expenditure is directed toward detailing. Historically, detailing has been the pharmaceutical industry's primary promotional instrument. Our aim in this Article is to provide an integrative review of the academic research on the effect and role of detailing. We highlight the main findings that arise from the medical, legal, economics, and marketing literature. Finally, we propose an explanation of the pervasiveness of detailing over a drug's life. We conclude by proposing how an increase in the efficiency and effectiveness of this expenditure can benefit firms, physicians, and patients.