This paper reviews current and recent research in the area of vapor intrusion of organic compounds into residential buildings. We begin with a description of the challenges in evaluating the subsurface-to-indoor air pathway. A discussion of the fate and transport mechanisms affecting vapors along this pathway is then presented. Following this discussion is a brief overview of current Federal regulations and proposed guidance concerning vapor intrusion. A review of site studies involving vapor intrusion that have been published in scientific literature is then presented, with a focus on evidence of the extent of the problem. Published approaches to modeling vapor intrusion are presented next, followed by conclusions and ideas about future research needs.