The Colors of Space (SF Classic)

Bart Steele, the recent graduate of the Space Academy on Earth, learns that his father has been murdered but has sent him a message: "Bart, I send money and instructions by my friend. Do as he says. Don't go home, Dad." In a far future space travel is common, but the secret of traveling faster than the speed of light is jealously guarded by a non-human race, the Lhari. Lhari are the species that is color-blind in the sense that everything they see is monochromatic. The pace is relentless and Bart must extort the secret from the Lhari by going undercover as one of them.