The Prophecy of Bane continues the strengths displayed in Collins' first book in the series, Gregor the Overlander. The book moves along quickly and smoothly with few if any slow spots; the major characters, if not minutely detailed, have enough personality and reality to hold one's interest and concern; and the setting, which as in the first is probably the weakest element in terms of vividness, is at least interesting enough in general terms so that its lack of detail is not much of a flaw.
As in book one, Gregor enters the Underworld to save a family member. In book one it was his father; here it is his little sister Boots. One sees the freshness and originality early on in the book as the quest quickly changes from what the reader first assumes it will be--the search for Boots--to a more dark journey: Gregor's quest to hunt down and kill alone the Bane (the prophesied future king of the Rats). Without giving things away, there are other such surprises in store for the reader; not just surprises of plot but also surprises of genre, so one doesn't feel stuck in the same old young adult fantasy quest rut. The book is also darker than most young fantasy, and the darkness runs from start to finish, beginning with the fact that (as opposed to what one would expect in the genre) not all is well since Gregor's "successful" rescue of his father in book one. His father hasn't come close to recovering and the family is paying both an emotional and economic price. This sort of reality, and the attention paid to long-term effects (with his father's illness as well as other events from book one) is one of the ways Gregor is distinguishable from much of what is out there. Another way is how death is not simply an abstract idea in this book but a solid and saddening presence.
The end or near-end is a bit weak in comparison to the rest of the book as it seems to have Gregor acting a bit unbelievably with only a nod to contriving an explanation (more detail would ruin a surprise). That's the only major weakness in the novel. Once again, a few of the characters could be more fully formed, the setting certainly could be more fully detailed, but one understands why Collins may have traded detail for speed and in reality, the flaws are relatively minor in comparison to how the story and main characters hold interest. Some of the lack of detail is also clearly intentional, as at least one more Gregor book is obviously on the way. If the first two are any judge, one can hope for even more. Strongly recommended for "older" young readers. Younger ones can certainly follow the book, but the context and setting (an world at their feet filled with giant mankilling rats) along with the few deaths might be a bit much--parents are the best judge. The parents themselves, however, might be pleasantly surprised by how much they enjoy it if they pick it up.