A tad heavy-handed and positively laden with tropes, The Invisible Library is still a fun little fantasy romp sure to push all the right buttons for many readers. Irene, our imperfect heroine, is an agent of the Library, an entity that stands apart from normal time and space. Librarians collect books from across the alternate worlds, and there are many, many alternate worlds, each with its own blend of science and magic. When she's saddled with a student and sent on a rather opaque mission to a quarantined alternate, things go awry. Fast.
The story manages to be both original and highly derivative at the same time. Certain aspects we've seen again and again from fantasy writers, but there's enough new material to make the book enjoyable. I'd be surprised if anyone who isn't a bookworm could really get into it, if only because the premise of the Library, a main character in and of itself, is to simply save and love books. There are about a bajillion literature references, of course, making it practically nonsensical to anyone who doesn't read much or at least have a pretty good knowledge of Western literature. The writing is nicely descriptive and there's certainly a lot of action to keep things moving along. But readers with a lot of fantasy books under their belt will probably be more exasperated than thrilled with the theatrics. We've read this story, over and over; there's just not enough originality to lift it above the quotidian. Readers who aren't generally drawn to fantasy might find this a little more interesting; it certainly appeals due to its average length when stacked up against behemoths like The Wheel of Time or The Song of Ice and Fire. I'd recommend this to the rather specific subset of reader who loves books but doesn't read widely in fantasy; most others will want to look elsewhere.