According to research, investigative psychology covers all aspects of psychology that are relevant to the conduct of criminal or civil investigations. The overarching aim of this special journal issue is to discuss how psychological research can help solve concrete problems that occur in investigative contexts. The eight papers (investigative interviewing of witnesses, interviewing cooperative witnesses, interviewing suspects, suspect deception, eyewitness identification tests, malingered memory problems, offender profiling, and jury decisionmaking) in this issue will discuss the research questions that have driven the research agendas within each research theme, and make clear how utilizing scientific knowledge can help practitioners with the problems they encounter in their daily work. Two basic questions were asked: 1) what are the main problems to be identified within the particular research area of investigative psychology, and 2) which solutions can psycho-legal research provide in order to solve these problems? The experts outlined 'what works' in their domain of expertise. References