If you're new to Trek then this book will ease you into trek tech and lore. However if you own any of the previous Tech Manuals such as Mr Scotts Guide to the Enterprise or the Next Generation technical manual then I think you'll be disappointed by this book. As mentioned in previous reviews this book is very light on the technical aspects of Star Trek and as a result you can read page after page without really learning anything you couldn't grasp from watching the shows.
There are some nice CG renders of the ships, however many of the technical illustrations are massively inaccurate and strike me like they were constructed by someone who was drawing the Enterprise for the first time and didn't quite understand what they were looking at (the technical illustration of the Enterprise D is especially disappointing). The book is also littered with numerous shots from the TV shows and films which make it feel more like an episode companion guide.
For people just starting to explore Trek it's a reasonable book; for those of us who've followed Trek for a little longer it's a book you'll flick through, put on your bookshelf and forget.