I currently do "some" Star Trek work.
I am
not an in-house writer for Pocket Books. Currently, there are no in-house writers for the Star Trek line. Now, are there writers that the editors will turn to first? Sure, because they know they can turn out a book in X amount of time who have a good grasp of the characters and enough knowledge about the series that continuity errors are kept to a minimum.
Now, normally, places like Pocket want you to have an agent first but not always. I came in through the side door because I was willing to write for their e-book series first. The editor, whom I had met at several conventions and had worked with on an Incredible Hulk anthology back in 1998, knew I was former military and he was looking for someone who could write a "Dominion War" novella that wasn't a typical run the starship in and start shooting story. So, I pitched, we kibitzed and eventually, I had a story, which led to my latest work (coming out this month) and hopefully will lead to more work in the future.
Also, you're
not out a manuscript if you work in this world. No editor will look at an unsolicited manuscript for a licensed property. I have some other work out, (still waiting to get a response) for a project I heard this editor had picked up. When he told me I could pitch something, I sent a two-page pitch/synopsis to him. He didn't like X but did like Y so he told me to repitch it (which I did). Now, it's at the licensors waiting for their approval.
If they like it, then I'll have to do a (loose) chapter breakdown, which again the editor and the licensor must approve. If that's approved, then I'll be given a contract and told to have the book done in X months. Once I finish writing it, then the editor has to approve it and so does the licensor (of course, edits and revisions come in here).
Only when the licensor is perfectly happy that I haven't mucked with their intellectual property does the book go forward. But, until I get the go ahead, I do not start "writing the novel". Licensors have "interesting ideas" what puts their property in the best light, but they own the property, so that's their right.
I'm also a member of the International Association of Media Tie-In Writers,
http://www.iamtw.org,which has members who've been doing tie-ins since the 1960s (Gunsmoke, The Man from U.N.C.L.E., F-Troop, etc. (mostly published by Whitman - .99c hardcovers)) to people like myself who're just getting into the business. It's been a great learning experience working with these people as well as getting good tips about possible jobs, how people work to very tight deadlines (novelizations of movies have to be out the same time as the movie, for example), and having a place to discuss contract issues/concerns.
And I agree with Claudia Gray. It's still writing, with an even more demanding audience because they have pre-conceived notions of what the character "should be like" and they're quite vociferous if you stray from that.
Now, do I want to sell some of my own stuff eventually. Oh hell yes. But, it's been a lot of fun so far doing the tie-in stuff and I'm proud of everything I've had published so far.