The aim of An Introduction to Criminal Psychology is – as its title rather plainly suggests – to introduce the topic of criminal psychology. Although mainly intended for undergraduate students the book may be of wider interest to general readers, policymakers, and academics from other disciplines who are interested in finding out more about the causes of crime and different ways of responding to criminal behaviour. The word ‘psychology’ in the title should clue readers in to the main focus of the book, but my aim throughout is to explore how psychological explanations and approaches can be integrated with other perspectives drawn from evolutionary biology, neurobiology, sociology, and criminology. Although pitched at an introductory audience with no prior knowledge of the field one of my aims was to ensure that the book is firmly anchored in the research literature. Unfortunately the picture of crime (and criminology) that we often receive from the media does not necessarily provide a very accurate portrait of crime in society or the activities of criminologists and criminal psychologists (much to the disappointment of many an undergraduate criminology student!). As such, the book has a lot of references, and I hope that it can serve as both an introduction to the topic and a useful reference source.