For the law enforcement officer and the civilian who may be in a situation that requires the use of a handgun to stop a lethal threat action, it is important that the person differentiates between the crass, glib and self-serving advertisements of ammunition vendors and the reality of how, what and why effective stopping power occurs. Factors to consider are the physiological response, the psychological response, the time frame parameter and bullet efficacy. Of these four factors, only bullet efficacy can be somewhat controlled by the person, this only by understanding how and to what extent the bullet contributes to the degree of stopping power obtained. A number of concepts / formulae have been included so as to permit the reader to consider their merits and whether or not they are consistent with the reality of biology, physics and other relevant sciences. Finally the material in this book is intended to permit those persons to instruct, teach or make decisions...