Congratulations, Gene! Yes, it's a young Theodore Roscoe. When I first posted the photo I was just thinking of Web of Conspiracy. Later I remembered he also wrote The Lincoln Assassination, April 14, 1865: Investigation of a President's Murder Uncovers a Web of Conspiracy. This is a much shorter book than Web of Conspiracy, and I think it's meant for younger readers (maybe 6th grade and up).