Tom Clancy's

The phrase "Tom Clancy's" on the front of a book, and not just "Tom Clancy" without the possessive, probably means "not by Tom Clancy". As Clancy became more successful he practically became a franchise. A great many books have been written, and computer games made, with Tom Clancy's name on the front but no indication of what hand, if any, Clancy himself had in their production.

Generally, in the series like Op Center, Tom Clancy (with Steve Pieczenick, in Op Center's case) created the scenario for the books (setting, characters, perhaps some ideas for storyline), then unknown ghostwriters actually wrote the book.

The Op Center books I would refer to as "Clancy Lite" -- some of the same excitement as a Clancy book, but no meat behind it. The fact that Clancy himself didn't write it is probably why.