One major concern about this work is that the title might make some individuals think that it is a "true crime" book, or a "whodunnit." Nothing could be further from the truth. This is a history book, albeit a comparatively recent history that took place in the 1970s, and, as such, is exemplary in all possible respects.
It begins with a murder, and then another. A woman is killed, a man grievously injured, and a letter is sent to the news media. The killer gives himself a name this is the Zodiac speaking and provides a message written in code. So we start with three mysteries: the man, his motives and his message. The third is quickly cracked; the first hypothesized, but never definitively proven.