I met one of Shatner's ghost writers, Bill Quick, once. Funny guy and a good writer. He wrote most of Shatner's Tek novels, I think, and ghost wrote for many other celebrities as well. His personal tragedy was (and is) that he never managed to sell much of the books he wrote using his own name.
He did have an ego that was at least the size of Shatner's, but I think he told me the truth.