This was a very interesting book, with a fabulous beginning idea. The idea that Jill can turn into Jack for a few days each month and be a completely different person with a completely different view is very, well, interesting! The plot twists and turns, there's things to break your heart, and there's things that make you want to shout for joy. I would definitely recommend this book to anyone willing to read it who isn't put-off by the used language and many references to sex and sexuality.