Corsairs of Cthulhu is a rules and setting supplement to the Call of Cthulhu role-playing game and focuses on the period between 1650 and 1730 CE. Your keeper can set up your investigators as crew on a pirate or privateer ship, freelancers in one of the Caribbean ports who love the gold doubloon more than a foreign governments rule, or even provide your investigators with their own ship. Working together the investigators must face evil Mythos, real and imagined. Curses left by ancient civilizations and hidden nightmares around the world.

Corsairs of Cthulhu is not just a setting book, but also contains a full campaign, The Map of the Astronomer. This campaign will take your investigators to ports unknown, fantastical lands out of this world and come face to face with some of the most dangerous Elder Gods and dark creatures ever faced.