There aren't too many novels about Twin Souls that I've enjoyed. Quite a few books, either channeled or displaying various degrees of the "woo-woo" factor, exist, but novels -- well, not so much.
I found two that I read during the time before I wrote my novel, The Gemini Bond. The first one I read was Jennie's Reprisal. It is based on the author's experiences, I believe, of remembering her Twin Soul through various lifetimes. While it is an interesting read, it wasn't my favorite book. I liked The Teaching of Little Crow
better. I don't know why, but I could relate to it a little better. The characters came across as more human, and the story was compelling. It did contain extended passages about the author's spiritual beliefs concerning "I AM" affirmations, but those didn't bother me too much.
So, pick up a novel about Twin Souls for your summer reading! You may enjoy one of the above novels, or you may enjoy -- here it comes -- The Gemini Bond. Sit back and get reading!