A history of bookshelves, the physical design of books themselves, and to some extent the organizational systems for libraries. Might sound boring. But I think any book-lover, especially one interested in how things are organized, will find it engaging, as I did. Seeing books lined up vertically on shelves is so much the norm for us that it's hard to imagine finding books in other ways (although stacks on the floor are often a norm for me, too). Petroski looks in detail at all the ways throughout history that books have been kept safe, from the oldest scrolls stored in cubbyholes, to precious volumes safeguarded in locked chests, to various takes on shelving until arriving at the horizontal bookcases we are so familiar with today. He looks at library designs as well, and includes plenty of amusing anecdotes about book-lovers through the ages (I remember in particular Samuel Pepys, who was a book collector paramount to none; he had hundreds of books and apparently had to climb over the piles to reach his bed!) I found most intriguing the descriptions of heavy volumes so valuable (back when books were meticulously copied by hand and took scribes many years of their lives to create) they were actually chained to the shelves to thwart library visitors who might also be thieves. It led me to the title The Chained Library, a book that's been lingering on my TBR list forever now (mostly because my public library doesn't have a copy for me to read). As a little plus, the appendix has all sorts of suggestions on ways to organize your own library, from the usual subject or alphabetical arrangements to sorting by color and other whimsical methods. Overall intriguing and fun at times. The writing is pretty good, too. A lot of it is about engineering of shelving systems, but it's written in a friendly fashion that makes that easy to understand, open to the curious mind. Sure to interest any bibliophile who likes to mess with lists and shuffle their books every now and then (I rearrange my shelves every few years just for the fun of it).