A dark mystery has been buried beneath the sands of the Sahara for eons. In a basement in New Mexico, four poker buddies find reason to believe that a startling secret is out there, and these four amateur adventurers are about to uncover it.

Curiosity propels mild-mannered professor Will and his three friends to the Sahara to excavate a site where radar has detected trilithic stones hidden beneath the sand. There they stumble upon an ancient artifact that will change their lives—and the world—forever: a gateway between planets, linking Earth to distant worlds where they will discover wonders and terrors beyond imagining. Now each traveler must play a crucial role in unraveling an ancient mystery, the solution to which may reveal the true origins of the human race—if they can survive the journey back to Earth.

Jack Williamson published his first short story in 1928. He is the author of such classic science fiction as The Legion of Space, The Humanoids, and Darker Than You Think. He is the recipient of the Grand Master Award from the Science Fiction Writers of America, the Hugo and Nebula Awards, and the John W. Campbell Memorial Award for the best science-fiction novel of 2001. He lives in Portales, New Mexico.