This is the first time I've participated in this so I hope that I get it right! Amy at My Friend Amy posed the question "What's on your keeper shelf".
My keeper books would be any and all John Piper books. I've really come to love his books. They really make me think and contemplate my faith. My son the seminary student is also interning at Piper's church. Matt turned me on to Piper a couple of years ago. Pipers books are very rich and so full of content, it's like a full meal compared to the dessert of other books. Another would be the book "Captivating" by Stasi Eldredge, this book is one of those that you read a page and then have to absorb it for awhile before going on.
I know there will always be some Steinbeck on my shelves and probably something historical as well.