The book I'm most thankful for is Jane Eyre by Charlotte Bronte. Sure I'd read other books before then, but Jane Eyre was required reading in high school at a particularly crappy point in my life. I'd stopped reading for fun and was just going through the motions for school. Jane Eyre was the first book that I had to read that I decided was worth reading. I've read it several times since then and it never fails to disappoint. Now, whenever I'm in a funk, I find a good book.