Book excerpt: Criminal investigation has a high profile in the media, and has attracted widespread interest. Within the police it has been a rapidly developing field. Important scientific and technological developments have had a considerable impact on practice, and significant steps have been taken in the direction of professionalizing the whole process of investigation. Within police studies criminal investigation has now emerged as an important sub-discipline. Criminal Investigation provides an authoritative and highly readable introduction to the subject from somebody ideally placed to write about it, focusing on how police practitioners carry out investigations. It looks systematically at the purpose and role of criminal investigation; the legal, policy and organizational context in which criminal investigation takes place; the evidence and information that criminal investigators seek; the process and methods of criminal investigation; the knowledge, techniques and decision making abilities that practitioners require to carry out criminal investigations; how and why it is that some crimes are solved and some are not; the supervision of criminal investigation; and a review of some of the key contemporary issues that have a bearing on criminal investigation. Criminal Investigation will be essential reading for both policing practitioners (student police officers as well as officers taking higher levels of CPD within the police service) and students taking courses in criminal investigation, forensic sciences and investigation, police studies and police science, and other courses where a knowledge of criminal investigation is required.