I would highly suggest this book to anyone who is serious about learning how to work in UDK. Mr. Thorne does an excellent job of explaining concepts clearly and the images and downloadable support files are icing on the cake. All the book's images are in B&W which, admittedly, isn't ideal, but is forgivable given the number of images in the book and the cost of color printing. Also, the images are available for download on his website, which I found useful.
I have been learning to use UDK for roughly 6 weeks (after an 8 year hiatus from hobbyist game modifying) and have been using free online tutorials, the UDN, Epic forums and some game development training sites before having read this book and I find it to be as good as the best online tutorials I've come across so far [which, for the record, is everything on 3dMotive.com - those guys are great]. However, I could see how someone with no game development or programming knowledge would have a hard time with this book - it's not meant to be a primer or 'how to' for the complete novice. Instead, the author wisely focuses on UDK and admits that there are already enough sources to learn other skills such as programming, 3d modelling, game design, etc. If you are starting out brand new to game development, I would still suggest you get this book, but don't expect to be able to pick it up and work through chapters 1 - 14 immediately. That said, even a total novice could likely make it through the first few chapters with no issue.
At the time of writing this review, I am using UDK version December 2011, which is slightly newer than the version the author uses throughout the book. I found very few differences between the software versions until reaching chapter 12, Unreal scripting, then a few small differences caused problems for me (because I had zero experience with scripting prior to this book - those with some experience may be fine). Mr. Thorne actually addresses this fleeting value of the book by admitting that UDK is updated monthly and thus, is impossible for any written book to stay perfectly current. The best solution is to download the September or October 2011 version of the UDK when working through the book's examples. Once learning how to get through the content, it is a piece of cake to transfer that knowledge to the most current version. As I said, it's only in chapter 12 that the differences begin and given the complexity of the chapter's topic and the author's routinely clear explanations, I consider this a very small price to pay. You'll be hard pressed to find any other single source explaining the topic better.
The only complaint I can really make is regarding the physical book itself, which wasn't bound terribly well on my copy. This causes some of the pages in the last few chapters to be connected to the binding by the bottom third of the page, only. It could be something unique to my copy and it's really not a big deal anyway [to me, at least].
Lastly, I have to state that the author really went above and beyond, for me, by responding to an email I sent him. I was having a problem following the book in chapter 12 [due to December '11 UDK update] and honestly didn't expect an answer but didn't know who else to ask. I have never written an author directly before, so I can't say how common it is to get a response, but I was so pleasantly surprised to see a VERY thorough reply in my inbox just a few hours later! Now, please don't flood his inbox with requests, but take this as evidence of the author's passion for the subject and desire to pass that knowledge along.
I only wish I had found this book 6 weeks ago and it would have made my learning of the basics that much faster. Ultimately, I would suggest this book to anyone serious about quickly learning UDK.