This conclusion presents some closing thoughts on the key concepts discussed in the preceding chapters of this book. The book argues that there is a wealth of established psychological research and theory across numerous areas of criminal investigation, but that the depth of this research varies across individual areas or disciplines. The common element that underpins all the areas of criminal investigation is the human factors that underpin thinking and decision making and which are the root cause of most miscarriages of justice. The correct mind-set goes hand in hand with investigators' knowledge base, in that they must have the right knowledge to perform their role. Organisations need to have a training and knowledge regime that is optimal for transference to real life practice. Evaluation must be more than checking the mere application of a process and must be focused on both the quality of an investigation and the personal performance of the individual, the latter linked to personal development.