This is where the story really starts turning the heat up. We're introduced to Will, who hails from our world. But one warning: This is not a standalone book, like Book One is. Don't even start reading Book Two if you don't have Book Three by your side, waiting for you to pick up breathlessly the minute you finish The subtle knife.
Unlike a lot of trilogies, I don't feel the second book here really lets down the first one. The stakes are still high (although not quite as personal, overall); it's still fast-paced and packed with action; and while Will is a great new character, it's good that Lyra's still the other main character.
Again, this is a very good book, and I'd recommend it — after reading Book One. Pullman seems to assume everyone will have already read the previous book; so if you don't read Book One first, you might be pretty lost as there are constant references to it.
OK, I know this isn't exactly a long review, but honestly: this is more Part One of Book Three than a standalone book. Next week: My (much longer) review of Book Three!