For three years, an art collective called Combustive Motor Corporation (Chris Noble, Caleb Scott, Jack Warren, and Alex Wright), has obsessively researched and documented the work of UFO 907. The culmination of their work, U.F.O., is a broader, more conceptual look at the subject than a simple collection of images. Referring to it as "the phenomenon of U.F.O. graffiti occurring throughout New York City," they are analyzing the semiotics of graffiti alongside the cultural representation of aliens. These elusive symbols spray-painted in enormous letters at the tops of high buildings are as mysterious as crop marks. Who did them, and why, and how is it possible that it went unwitnessed? Alongside the images is the artists' research into actual sightings and accounts of extraterrestrial activity, dating back to the '40s, and an exploration of aliens in art, beginning with cave drawings and going up to David Bowie. UFO 907 doesn't actually appear in the book, either because the artists couldn't track him down (not unlikely) or for effect. CMC is going more for the way we interact with symbols than an actual explanation for them.