Despite the obvious importance of eyewitness information in criminal investigation, police receive surprisingly little instruction on how to conduct an effective interview with a cooperative eyewitness. More than half of police departments have no formal training whatsoever for newly appointed investigators. Most texts in police science either completely omit the issue of effective interviewing techniques or provide only superficial coverage. This manual provides guiding principles to effective interviewing, with specific techniques to be used and others to be avoided. There are principles of memory retrieval so that the reader will understand why to employ specific techniques -- for example, when to use open-ended versus direct short-answer questions, effective use of pauses, asking follow-up questions, cues to name and number recall, etc. There is the strategy of interview sequential structure -- that is, what to probe for at the beginning, middle, and end of the interview. Also included are practical exercises and real-world experiences. The book will also be helpful for attorneys in conducting investigative interviews.