This DVD is very helpful in receiving simple instruction from Jim Craig on how to defend one’s self when one’s physical life is in danger. Jim Craig demonstrates various techniques in easy-to-understand lessons and includes a student, a teen aged girl, to show that size, sex, and other physical attributes need not prevent one from defending one’s self. Craig comes across as both knowledgeable and down to earth. The “21” stands for the number of days in which a student can fully learn the various methods which are taught by Craig.