Exquisite. I could wax lyrical about how the authors took the traditional weakness of the collaborative novel and made it a strength. I could go on about how they made me enjoy a time travel story, not something I would normally do. I could rave about the pull of the interactions between the protagonists and how choice it was that this was the main plot engine. Let me just say instead that this is definitely recommended. If you read my reviews, you should read this.