What is the most unusual book you ever bought?

I rather obsess about reading books...books about books....about bookshops...about authors...When I happened upon Abebooks' website, I found an afternoon's distraction in their booksellers' profiles. The piece below, by the owner of Yankee Book & Art Gallery, deeply moved me.

"...the one that I found the most interesting was a book whose title I can't remember and was not particularly significant.
It was a religious book published in 1854 in Richmond, Virginia. What made it so unusual was the hand writing in the book. The hand writing was by a Union soldier who wrote "This book was captured while the battle raged. Taken from a dead confederate soldier's body. At this battle my best friend went down. If you should find this book on or about my body please return it to my mother (an address in Pennsylvania was given) and tell her that I died gallantly on the battlefield."

One of my own experiences many years ago was at an independent bookshop in Wichita, Eighth Day Books. Browsing through the shelves while sipping a cup of coffee (is there any other way to enjoy a bookstore? Books bring to mind coffee...coffee brings to mind books), my hand landed upon a book with a completely nondescript spine...What caught my attention, I'll never know. However, the title of the book was intriguing - Working in a Small Place: the making of a neurosurgeon. As I read the back cover where it described this surgeon's work with, I realized that this was exactly the type of information that a friend needed to pass along to her mother, who was suffering from excruciating facial pain known as "Tic Douloureux". I promptly paid for the book, drove to my friend's home, and presented her with it. She, in turn, gave it to her mother....who contacted the neurosurgeon...who set up a date for surgery. Within the month, she was flying across the country to have the operation - which was a complete success. I will never forget the awe I later felt at such a profound sense of intuition. Books have that sort of effect on me...alot.