GURPS Traveller is a 12-book series with 12 released primary works first released in 1998 with contributions by Loren Wiseman, Loren K. Wiseman, David L. Pulver, Martin J. Dougherty, Neil A. Frier, John M. Ford, David Pulver, David Thomas, David Nilsen, Andy Slack, Douglas E. Berry, Steve Jackson, Jon F. Zeigler, Thomas L. Bont, Christopher Thrash, Robert M. Prior, Paul Drye, Hans Rancke-Madsen, and Robert Pryor.