This book informs the reader how to approach the investigative process using investigative thinking. This book provides key definitions and protocols that an investigator should understand to carry out the investigative process. It introduces the three big investigative errors along with graphic illustrations of "The Investigative Funnel" and the "S T A I R Tool" to illustrate how each of these concepts in the investigative progression. This book is designed to assist the student in developing their own structured mental map of processes, practices, and thinking to conduct criminal investigations.