A jcwren tag would be perfect for this task...
(like location, birthday...)

Few tags would do fine:
Book-Offered
Book-Needed

His page whould be a perfect place to look for available/needed books.

UPDATE : I must say why I prefer this way, rather than SuperSearch.

The stats page allow us, by it centralized stat gathering a way to got global stats about the way books move.
I mean with few property inside some tags,
(namely: title of the book, people who gave/received it, date it was given/received)
we could be able to know how many times a book was given, who get/gives the books, and a lot weird/useless stats...
(The average time a book stay in someone hands ?)
(Most asked book ?)