In the past few years, I have read many UX books, and most of them were either extremely boring or very badly written, so I approached this one with a lot of cynicism. Luckily, it is neither boring nor badly written: it actually has a very good pace, talks about most aspects of User Experience just in the right length, and maintains a tone throughout that relaxes you and makes you feel that you're actually doing something that you enjoy.
The authors maintain the position that some UX work in design is better than none, and show ways how research, design and production can be influenced by User Experience work (performed by you, the reader) without big budgets or a sense of perfectionism.
Having worked in various companies large and small for UX teams both successfully and unsuccessfully, I found that the relaxed approach by the authors resonated with me. It's a bit like books by Steve Krug, but less descriptive in what needs to be done. "Undercover User Experience Design" rather gives you a range of possibilities to tackle problems along the way, and it's up to the user which one to pick. The book quite masterfully describes the techniques with just the right amount of detail: if you're okay with a bit of uncertainty, you can probably do the exercises straight away, but if you're a bit anxious because you've never done it before, the book gives you plenty of leads to follow up on.
I rarely recommend a book for both beginners in UX and seasoned professionals, but I felt that it spoke very well to both parties: beginners get a 5-star introduction into what can be done, a bit of how-to as well, while professionals can use it as a quick-reference guide in case they hit a snag somewhere in their projects.
Oh, and it's under 200 pages, which makes it much more likely for you to actually read ;-)