He wasn’t a great writer, but it’s definitely a little odd that none (I’ve ever noticed anyway) of his series of books were ever made into a movie. “Inherit the Stars” would make a massive-ass film, and it has built-in sequels. If I had the cash, I’d produce it, and get Terry Gilliam to direct it, and watch it go over budget by $100 million I’m sure. ;’)
I think the problem with a lot of his books was that they were too intellectual. My personal favorites were “Thrice upon a Time” (very interesting ideas about time and reality), “The Genesis Machine”, and “Voyage from Yesteryear”. I though “Inherit the Stars” was good, but a bit too long—and the two sequels were downright silly. My pick for a movie would be “Voyage from Yesteryear”.