This chapter provides a general introduction to the use and meaning of implicit measures in social and personality psychology. It explains what implicit measures are and in which sense they may be described as implicit. The chapter provides an overview of the currently available paradigms, including details on their task structure, reliability, and applicability. One of the most frequently used paradigms is Greenwald et.al'.s implicit association test (IAT). The chapter also provides a brief overview of the insights that can be gained from dissociations between explicit and implicit measures with regard to the prediction of behavior, the prediction of biases in information processing, and the formation and change of mental representations. It discusses several assumptions that are quite common in the interpretation of implicit measures, yet questionable on the basis of the available evidence.