Huh, one of my favorite authors, Martha Wells, turns out to be writing Stargate Atlantis books.
My knee-jerk reaction to mainstream or semi-mainstream authors writing books ”for shows” instead of on their own is usually “yuck.” Then I remember some non-yuck, definitely worthwhile stuff written for the various SF universes, including -
John M. Ford, Star Trek, How Much for Just the Planet? [Hilarious, well worth tracking down]
Larry Niven, Star Trek Log (the animated half-hour series), The Soft Weapon (after a short story of the same name).
James Blish, lots of script adaptations of the original Star Trek.
Greg Bear, lots of books in the Star Wars universe [which normally I can't stand]
I’m sure there are other fine examples. (Note that the Serenity script adaptation was a miserable piece of poo. They should have had Bujold or Varley or even - God help me – Ellison pen the damned thing).
Robert Jordan did a great Conan. (http://en.wikipedia.org/wiki/Robert_Jordan#Conan_the_Barbarian)
Pedantic, but:
The Niven story was indeed “the soft weapon”, the ST:A episode was “the Slaver Weapon”, and the adaptation by Alan Dean Foster is what was in Star Trek Log.
Which lets me add:
Alien, Alan Dean Foster. I enjoyed the extraneous details added to the universe, which spawned Dark Horse’s further expansions with the AvP comics, leading to a novelization of the comic series by Steve Perry (Matador series, not Journey singer) with yet further liberties taken.
Funny how these things spark long chains sometimes.