I learned about this book from a coworker at the library and am really glad I sat down to read it. This isn't a very long book, and it doesn't necessarily have to be read all the way through to glean the important points. Nevertheless, I really wish we could make every one of my coworkers read this book!
The author uses actual research he's done over years and years to glean new insights into the world of shopping and the people who shop. He researches everything from seat placement to aisle width and endcaps. While he never talks about libraries specifically, the information he presents is useful in any retail or service setting.
For example, the "butt-brush" effect is surprising and insightful; it's the concept that browsers, women especially, will only linger briefly in an area where they are being brushed or crowded by other shoppers or store employees. It cuts down on browsing time and the comfort of the customer, which leads to less sales, especially from crowded racks.
There's also information about where to place shopping baskets/bags, where to place items targeted at children and senior citizens, and how the dynamics of the marketplace are going to change over the next few decades.
I highly recommend this book for anyone who works with the public. Once you've read it, make your boss read it. It's worth it.