Ptolus: City by the Spire is a six issue limited series published by Marvel Comics along with the Dabel Brothers Productions. It is based on the Dungeons and Dragons campaign setting created by Monte Cook. Cook was also the writer of this series, having vowed to focus on fiction writing instead of RPG supplements shortly after he released the Ptolus campaign setting in August 2006. This trade paper back was initially released on July 5, 2007 for the price of $14.99, ISBN 978-0785125914.