This really is one of the best academic books on fandom, if not the best. Hills has a remarkable ability to read in, through, and around established theory, and yet also has a nice knack of forcing theory to account for grounded realities. Each chapter boldly approaches fandom from the standpoint of an existing binary in fan studies, and as a result, the book shatters through multiple impasses (and sillinesses) in established work to date.
Fan studies is such a maligned sub-discipline in a field (that of cultural and media studies) that all too often prefers mea-culpa lashing of the media body, and that prefers disgust with or pity of the fan to any actual attempt to understand him/her. But the strength of a book like this defies critics of the sub-discipline. Indeed, I don't think it's too much to say that fan studies really comes into its own with this book. Hills has opened up ground for future work, through careful reading of past work and a sense of what is tragically missing.
As such, I would highly recommend this. If you are looking for empirical work, this is not your book (although Hills reads others' empirical work well), but if you want a macro picture of how all that work fits together, this is it.