This handbook on information security was originally published for businesses in 1989. The book's intent was to acquaint the reader with the basics of information security. It did this by looking at what is best described as business intelligence. Although, surpassed by more modern methods and techniques, this classic text is considered as one of the first to promote the function, structure, and operational methods involved in business intelligence as a way businesses could establish, and maintain, a high level of information security (i.e., business counterintelligence), thus minimizing the threat posed by business adversaries. This 2020 reprint brings back into focus this historical work by research criminologist Dr Henry Prunckun, who has gone on to write such books as "Counterintelligence Theory and Practice" (Rowman & Littlefield, 2019), now in its second edition.