Written in My Own Heart's Blood by Diana Gabaldon
This is the latest installment in the Outlander series. If you haven't read the other books, don't start with this one. This is definitely a series that needs to be read from the beginning.
I loved it so much I read it twice in a row. The second time I picked up on several things that I had missed the first time around because I was reading so fast the first time around.
For anyone who isn't sure if they would like this series, the television channel Starz is premiering the Outlander series on August 9. Watch it and see if you like it. That's what got me to finally read the Game of Thrones books.