This movie varied substantially from the book, although not as far as other movies based on Clancy novels.

Kirby's page turner reads like a Clancy novel but is not a medical text.

Lake loved Clancy novels.

The "cremated alive" hypothesis also appears in several Clancy novels.

This is one of only three Clancy novels not falling into the Jack Ryan universe, the others being Red Storm Rising and Against All Enemies.

So the question is, where do Clancy's guys go when there's no Clancy novel?

"It's very much a Tom Clancy-like, Washington-based thriller, that we deliberately scheduled when there was no new Clancy novel," Mr. Romanos said.

Neither character in the Clancy novel is black, and indeed black admirals in the U.S. Navy are about as common as shore birds on the high seas.

It's the kind of computer game that is easily turned into a Clancy novel, for the same reason that Clancy novels are easily translated into films.

Four films based on Clancy novels featuring Jack Ryan have been produced starring three different actors as Ryan.