Book jacket design of The History of White People

I saw or read about The History of White People (by historian Nell Irvin Painter) several months ago and put it in my mental checklist of books to read, but forgot about it until I was browsing around in 192 Books the other day.  The title is attention-grabbing by itself; it's probably the first book that proposes to tell the history of the "white" people, whereas books about other races, cultures, or even subsets of "white" people are far more common.  (Note: In her introduction, Painter discusses the problematic aspects of discussing race in general, and the catch-all term "white people/s.") 

But what really caught my eye was the book's spine, which, unlike almost every other book you might see, contains horizontal text providing a brief synopsis of the book.  For this very reason, the book stood out on the book shelf.  Putting a description on the spine conveyed the message 'Look at this, this is important, you should be reading this.'

It would be nice to be able to go to a bookstore and scan the spines for whatever seems interesting.  But if every books started putting descriptions on the spine, shelves could look cluttered.  Plus it would limit the design possibilities for individual books.  I can also understand why designers might not want to place descriptions on the spines.  There can be a certain amount of mystery in a book title, which can make you intrigued enough to pick up the book and look at the table of contents or at the inside flaps of the book jacket.  And getting the book in your hands is a closer step to getting you to purchase it.  In any case, putting text on the spine was a neat tactic for The History of White People.