"It's said that the thing one never forgets about a person is their gender.
THE RESIDENTS are genderless.
The next most memorable feature is the face.
THE RESIDENTS are faceless.
The third thing we remember is personality.
THE RESIDENTS have no personalities."

The above just about sums up everything you need to know about The Residents.

If you're still not happy then Matt Groening, creator of "The Simpsons" and "Life In Hell" puts it this way: "There is no true story of The Residents. You should know that right off. The secrets of The Residents will never be revealed by anyone but The Residents themselves, and so far they aren't saying much. [...] Part of what The Residents are about is their camouflage, and any understanding of them must take into account both their organized sounds and their organized silence."
One fact is the origin of the name : they mailed a tape in May 1971 to Hal Haverstadt of Warner Brothers Records, in a bold attempt by the anonymous group to secure a recording contract with that company. Hal mailed the tape back months later with a short rejection notice addressed to 'Residents' -- hence the group's name.