This overview of the Addiction supplement on 'Research Perspectives on Alcohol Craving' has three objectives. The first is to familiarize readers with the variety of theoretical models relevant to craving and the definitions of craving generated by them that are discussed in the supplement. These include phenomenological models, classical and operant conditioning models, the incentive-sensitization theory, a tonic-phasic model of dopamine system regulation, cognitive social learning theory and the cognitive processing theory of craving. The second objective is to provide a brief summary of the methodological articles which focus as a whole more on what can be done than on what has been done in alcohol craving research. The final objective is to emphasize the potential importance of transdisciplinary research--research that integrates components of different theoretical models--for delineating the role of alcohol and drug craving in the complex biobehavioral process known as addiction. It is the hope of the guest editors (the authors of this overview) that the Addiction supplement and this introduction to it will contribute to development of a framework for future transdisciplinary research on alcohol craving.