Apparently, Jack Williamson has been writing for a long time. He has dozens of books that he's written. But I had never heard of him until the Science Fiction Book Club featured one of his books, Terraforming Earth. After reading the book description, I decided to order it, and really enjoyed it. It wasn't until after I read it that I found out just how prolific Williamson was. In fact, he's the person who originally came up with the term "terraform". He published his first SF in 1928. Terraforming Earth was published in 2001. Even if he never writes another book, that's a long career.