DS, signed “Cassius Clay,” one page, 8.5 x 11, stamp-dated April 25, 1963. Rider for a previous Screen Actors Guild agency contract for an undisclosed motion picture, with Clay hiring an agent “in the entertainment industry.” Signed at the bottom in blue ballpoint, “Cassius Clay.” Small portion of another signature lightly overlapping beginning of Clay’s signature, torn punch and staple holes to top edge, and one paragraph crossed out, otherwise fine condition. JSA/Mike Gutierrez Auction LOA and RRAuction COA.