There's no flair to the book; and compared to how well-written Matthew Stover's novelization of Revenge of the Sith was (which I read last year and which genuinely excited me), that was particularly disappointing. It's mechanical writing: this happens, this happens, this happens. Attempts to be poetic and more descriptive often don't work. Reading that the taun-taun had a "llama-like" head actually made me think "They can't know what llamas are in the Star Wars universe!" And there are (in my opinion) far too many exclamation points in the descriptive text for the often quiet, sad tone of Empire: it comes off more like the infamous "carnival barker" trailer for the film (by the way, the date at the front is wrong, as there's no way that trailer could've been done in 1978).
It could've been editorial constraints that kept the writing damped down like that; at the time, the known Star Wars backstory consisted of the first film, Alan Dean Foster's ghosted novelization of it, a handful of non-canonical tie-in books like Foster's Splinter of the Mind's Eye, and the insane (and massively non-canonical) Marvel Comics series. (Not to mention the Star Wars trading cards that had Luke a few years older than Leia. Oops. Heh.) We also didn't yet have Brian Daley's radio adaptations, which I believe are considered canon and which expand the films in interesting, worthwhile ways.
By the time James Kahn's novelization of Return of the Jedi came out in 1983, George Lucas and the other screenwriters had firmed up more details of the Star Wars universe, and Kahn could hint at more of what had come in the time before these three films. His book does have the first, fleeting flashback to Obi-Wan Kenobi leaving the greviously wounded Anakin to die, something not seen onscreen until 22 years later. I'm going on mid-Eighties memories here, as that's when I read Kahn's book, but I remember liking it and enjoying its sense of "bigger history," which is part of Star Wars's appeal: in each film, we're dropped into the middle of the action and we catch up, picking up on details as we go. There are odd additions that don't jibe -- didn't Kahn's book say that Uncle Owen and Obi-Wan were related? -- but I don't remember there being anything really jarring; they're more the "James R. Kirk of the Starship Enterprise" sort of niggling differences, as opposed to the "Greedo Shot First" differences. (Again, heh.) I wish Glut had had the chance to do that himself. Are his other books worthwhile?
I appreciate a well-done novelization, something adding detail and depth to a movie's story, and I'm lucky to have found people who are good at them: Peter David and Keith R.A. DeCandido consistently pull off well-done novelizations in between writing their own works. Orson Scott Card's sole novelization, for James Cameron's The Abyss, is a really solid work (and which even had an influence on the film; his chapters on Bud and Lindsay's early lives were given to actors Ed Harris and Mary Elizabeth Mastrantonio, and they worked them into their characters' backstories). George Gipe's Gremlins adaptation is hilarious, and pulls off some fun writing tricks (over 20 years later, I'm still impressed that Gipe wrote a two-word chapter). And as a Caitlin R. Kiernan fan, I appreciated her Beowulf novelization, and I'm also glad that that book gets her name seen by many more people. Let that lead to more readers for her, okay, please? I want her to be able to keep writing.
This has been a review. From a certain point of view.