The Book on the Bookshelf is Henry Petroski's sly look at how books are stored, and have been stored for centuries. It's sly, in part, because to tell you this he has to tell you the history of the book itself, and this of course leads him off in different directions. You learn much about not only books, and bookshelves, but scrolls, printing, various sorting systems, printing and spelling conventions over the years, and various other minutiae. If you're interested in this sort of thing, like I was, it's very interesting. I was fascinated to read, for instance, that the British publishing industry changed about a decade ago, and began printing their titles on the spines of books oriented the same way we do it. Previously they had printed the titles upside down (from our point of view) and the two books I'm referring to are old enough to display this. I'd noted it, but never knew why they were like that. Now I do. I'd recommend this book to anyone who's interested in books, publishing, and the history of those things. I will warn you that the author does tend to get into his subject, digress a bit, and run away with his topic now and again, but I generally found this characteristic charming rather than annoying.