Zodiac (1988) is Neal Stephenson's second novel, which tells the story of an environmentalist uncovering a conspiracy involving industrialist pollutors and bicameral minded Satanists in the Boston Harbor. The "Zodiac" of the title refers to the brand of inflatable motor boats the hero uses to get around the city efficiently. His opponents attempt to frame him as an ecoterrorist.

The protagonist is modelled after eco-activist Marco Kaltofen , who did such things as plug illegal outflow pipes as portrayed in the book.

ISBN 0553573861, ISBN 2207252647, ISBN 0871131811