John C. Tibbetts is an academic and critic. Among his many writings have been interviews with and profiles of Ray Bradbury and a comprehensive review of Bradbury's filmed and unfilmed screenplays.
But Tibbetts is also an artist, who has sketched many of the famous people he has profiled, and often got THEM to sign the work. Here are a couple of his Bradbury sketches, taken from his own website:
If you've seen a lot of publicity photos of Ray, you will recognise some of the poses which Tibbetts has adapted in his sketches.
See more of John's amazing gallery of sketches of the famous here - and read about how and why he does it here.