This practical guide enables readers to recognize, assess, and defend against gray behaviors—attempts to persuade listeners using fallacious arguments. It provides valuable tools for communicating successfully in a wide variety of public and professional contexts. The book examines 20 wide-ranging logical fallacies, cognitive errors, and rhetorical devices that may take place in persuasive communication, and discusses how to assess and respond the behavior of a speaker who may be disingenuously attempting to manipulate the listener—or who may simply be mistaken. Drawing upon research and insights from communication, psychology, business management, and human resources, it considers fallacies in reasoning not just as abstract formulas, but as a feature of communication encounters such as negotiations, interviews, public debates, and personal conversations. Each form of fallacious reasoning is exemplified by dialogues in both professional settings (such as interviewing and personnel assessment), as well as everyday interactions in public discourse. The book then provides self-assessment tests to ensure the reader can evaluate the grey behavior in these encounters. This book provides research-based skills and insights that will benefit students and professionals in fields ranging from communication, politics, management, human resources, organizational psychology, journalism, and anyone else looking to develop critical interaction skills.