"My Name is Memory" by Ann Brashares

Wow. Wow. Wow. Wow. Wow. 

This was one of the best books I've read in a while. It reminded me a lot of The Time Traveler's Wife. 

Daniel has lived for centuries, dying and being reborn over and over again. In each life, he searches for Sophia, the love of his life. Sophia has also lived for centuries, but unlike Daniel, she cannot remember her previous lives, or him. 

A really excellent read...I finished this very quickly and it's gone onto my "Books I want to own" list.