Craving is a core feature of drug addiction. It emerges early in the natural history of drug abuse disorders (e.g., O'Loughlin et al, 2003) and is experienced by the vast majority of drug-dependent individuals. For example, over 90% of daily cigarette smokers report having at least some craving when they have not smoked for a few hours (Tiffany, Warthen, & Goedeker, 2009). Clinicians who work with addicts know that craving is a central concern for their clients. Addicts worry and complain about craving while they are using, as they try to stop using, and even long after they have quit using drugs (Tiffany, 1990;Tiffany et al., 2009).Given the ubiquity and salience of craving in addictive disorders, it should be no surprise that there has been extensive research on craving. Indeed, craving research has exploded over the past 20 years, increasing 50-fold compared with the preceding 20 years (Tiffany et al., 2009). More recently, in the first half of the present decade (2001)(2002)(2003)(2004)(2005)(2006) there have been more than 2,100 published research articles with the words crave or craving in their abstracts. This research includes studies on the assessment, prevalence, conelates, manipulation, neurobiology, conceptualization, and treatment of craving in both humans and animals. Craving unquestionably remains a major issue for addicts and researchers alike, with most convinced that a 83