There are several categories of books, serious books that you are supposed to read, dreary books that are so dire that they are never finished, great books which live with you and change your life, page turning books which leave you wanting for more, not always great literature, but very enjoyable.
The Invisible Library falls into the latter category. This Who can resist a book where science fiction meets fantasy, where there are dragons and vampires, magic and science, and a Victorian world exists in an alternative universe. This is an extremely enjoyable read, so much so that I have acquired the next book in the series, The Masked City.