I grew up on a sailboat and sailed to different ports in Mexico, Central America and the Caribbean. Swapping books was practically a religion among the cruising community. Every port we came to, there were other couples and families aboard other boats and eventually folks would gather on one boat or another, or at some local bar and news, stories, and lots of alcohol was shared (soda or juice for us kids!). The other thing that was shared were books. It was very neat because some of the books had the names of the boats they'd been on written on the inside cover, and sometimes the month and year.
Two of these books stand out in my mind more then any of them.
One was Shogun by Clavell. I don't remember the boat we got the book from, but it was literally falling apart. The book is huge, over a thousand pages, and it was kept together by a big rubber band. When we got it, it was coveted by everyone, and eventually ended up being passed around in sections. At one point, my father, mother and aunt were all reading it at the same time.
The other book I remember wasn't really a swap. It was one of the first romances I ever read, Patricia Matthew's Love's Daring Dream, if I remember the title correctly. We literally found the paperback washed up on a beach. The front cover was missing, but the book was intact! We dried it out and everyone took turns reading it.
What was so funny was that even by the time I read it (I was the last of five) sand still fell as pages were turned.
We ended up swapping that water-stained book to another boat in spite of its rather pitiful appearance. I have to wonder if it ever stopped dribbling sand, and how many other boats it ended up on...