Bennett attended Farpoint, a convention near Baltimore, a few years during the aughts. When he gave a talk, I went, and I've heard him read from his memoirs.
Bennett had a publishing deal for his memoirs with ReganBooks. Unfortunately, ReganBooks shut down in late 2006 due to the double-whammy of the fallout of acquiring O.J. Simpson's If I Did It (which ended up being published by someone else) and an anti-Semitism scandal. When he last talked about the book at Farpoint, he didn't have a new publisher, but he was still working on the book. I'm not optimistic; publishing changed radically not long thereafter thanks to the Great Recession.
I will always treasure my memories of Bennett reading from the manuscript about his time with the Quiz Kids and choking up when he talked about how Leonard Nimoy saved his life and the conversation he had with Ingrid Bergman on the set of A Woman Called Golda.