I haven't read a Tom Clancy book in ages, but it was just very recently I learned that he had died, and that the books with Tom Clancy written all over them in the airports in fact were not written by him.
If you see "Tom Clancy" on the cover he probably wrote it but if you see "Tom Clancy's" that's a sign that somebody licensed his name. The same for Sid Meier's Civilization and such.