Thanks, Johnny Otis, for your strong and clear defense (The Book Review, March 16) of the great black American artists who've created our only unique national contribution to world culture. Thanks for exposing the insulting claim-jumpers who try to steal honor and credit from our black genius-originators of blues, jazz, gospel, rhythm-and-blues and rock . . . which would not exist without those black Americans whose souls were strong enough to make music in the face of poverty and hatred.