Who was the Zodiac Killer who terrorized residents of California during the 1960s and 1970s? The answer is still unknown. Readers take an in-depth look at the investigation that continues to fascinate Americans, discovering the details of the crimes and the search for the person who committed them. Additional information is presented through engaging sidebars and eye-catching fact boxes. Historical and contemporary photographs, including primary source images, help readers place themselves in the middle of one of the most famous unsolved mysteries in American history.