The breadth and depth of this manual will appeal to those interested in understanding what investigators do, as well as those starting out in the profession and veteran investigators wanting to hone their skills or seek professional credentials through certification. Topics such as investigations management, interview and interrogation, undercover investigations, and due diligence are discussed in depth, providing basic as well as advanced techniques required by professional investigators. The manual also describes the basics of preemployment background screening and provides a how-to approach to develop a comprehensive program that is compliant with current regulations. The chapters on evidence and testimony offer insight regarding topics that are often taken for granted. This manual is a must-read for anyone interested in improving their investigative knowledge and preparing for the Professional Certified Investigator (PCI) examination.