Why do people lie, and how can lies be detected? There is now a substantial psychological literature relating to these fundamental questions, and this book reviews the relevant research on lying and detection in detail, focusing on guidelines for best practices in detecting deception.
This book can be considered a good addition to Ekman's books. The author scrupulously analyzes the nuances of determining a lie or truth. The topic sounds rather complicated and requires preparation.
Of the important points mentioned is the style of communication (for example, different communication styles are used for attractive and unattractive people), which also affects the process. Quite a large part of the book is devoted to describing a specially developed technique for determining the truthfulness of statements, which is commonly used in some countries to interview sexually abused children.
A good overview of the science, such as it is, and a surprising number of practical notes from the author. (tl;dr: There is no definitive way to detect liars. All of the pop-sci body language stuff is rubbish. Go with your gut, and check everything checkable in the subject's statement. Polygraphs are only useful for scaring people into confessing, which doesn't work when they know what a polygraph is and how it works.)
This book is a must read for every PDD professional. It is a detailed study of the various Statement Analysis techniques avaialble for serious study. I have read this book several times and feel that I have yet to read it several more times. The theories and concepts espoused by Undeutsch are given more depth by Van Der Vrij. I keep this book near to me at all times.