The Myers-Briggs Type Indicator (MBTI) instrument was developed in the 1940s by Isabel Briggs Myers and Katherine Briggs as a marketable way to apply Carl Jung’s psychological theory to the general population. This book applies the theoretical framework of the MBTI to serial killers in an effort to show how it may be applied to criminal profiling. The analysis of twenty serial killers revealed their preferences in terms of decision-making as well as how they prefer to approach the outside world. Criminal profiling as a practice has been growing and evolving in the past century and can be enhanced with the use of MBTI typing to better understand criminals, identify suspects, and choose optimal interrogation techniques based on the subject.