h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

A textbook example of how films are better at some things than books. The source novel (by Roderick Thorp, which had a different title) was mediocre, with much less interesting characters. The Hans Gruber character really was a terrorist, not a thief, and John McClane was a lot less endearing than the character Bruce Willis played.

But then, since Die Hard is one of the greatest action movies ever made, the book would have to be incredible to live up to that.

What's also interesting is that the sequel was based on another, completely unconnected novel (57 Minutes by Walter Wager) which had already been developed into a screenplay. The producers were looking for sequel material, and decided that putting McClane's character into that book's scenario would give them a quick screenplay for the sequel. A very weird situation. I wonder what the author felt. I didn't think '57 Minutes' was too bad, but it was very different - the lead character was an aviation expert, and his final solution to landing the planes fitted that character - Bruce Willis could not have used his solution so they invented the (rather unbelievable) movie ending.