Among the major medical and social problems associated with chronic substance abuse is the manifestation of behavior commonly called addiction. Modern neurobiological research has focused on determining the cellular mechanisms by which the use of drugs of abuse leads to processes responsible for the development of compulsive drug seeking and drug taking, characteristics considered the hallmarks of drug addiction. In order to obtain a fundamental understanding of the adaptations that take place at the level of individual neurons and the neural circuits in which they operate, neurophysiological and molecular biological approaches must be used that can identify how these neurons and neuronal circuits are altered by both acute and chronic exposure to different drugs. This information must then be used to understand how altered activity in these neuronal circuits impacts the generation of specific aspects of addiction, including drug craving, withdrawal, sensitization and relapse. We believe a critical review of the approaches that are used to understand the cellular mechanisms underlying these phenomena will significantly advance our understanding of the addiction process. Further we believe that a venue that offers leading scientists, scientists early in their careers, and students the opportunity to discuss openly their research and hypotheses concerning how these state of the art cellular and molecular approaches can be translated into a better understanding of the human addiction will lead to greater consensus and further collaborative approaches to the study of addiction. Thus, the focus of the 2004 FASEB Summer Research Conference will be Modern Scientific Approaches to Drug Addiction: Relationships with Behavior. The conference will be held July 17-22, 2004 at the Omni in Tucson Arizona. The forum of the Summer Research Conferences provides an informal atmosphere that is conducive to presentation and discussion of up-to-date research findings in an interactive environment. There is only a single symposium or poster session at any given time and all participants dine together at every meal. To ensure an interactive environment, attendees will be limited to 162 participants and 38 faculty. The format includes invited presentations featuring prominent investigators with 15 minutes of discussion for every 30 minutes of formal presentation. There will also be a poster session limited to 50 posters, primarily from young investigators and student trainees.