The cognitive interview technique (CI) has received considerable attention as one of the most succssful interview techniques applied to real-life investigations, particularly police investigations. Although the general effects of CI are well documented, there are grounds for critical assessment. In this paper the theoretical principles behind the cognitive components of CI are provided. Variables that have been manipulated will be reviewed, as will conditions under which CI has been studied. The intention is to generalize across the major studies of CI and explore what patterns are present in the data. Issues are introduced that attempt to refine the theoretical underpinnings of CI, and provide direction for research.