I found this book absolutely riveting, and I can't recommend it highly enough.The three main characters are complex, interesting, mature men who know what they want (socially as well as sexually), and who are able to have conversations about their needs and interests. They make rational decisions, and when they behave a little less rationally, they're aware of it, and are able to discuss it. Basically, they're exactly the kind of people who should be involved in the kind of subculture the book portrays: solid, stable, dependable, thoughtful--and really, really hot.All of the secondary characters were equally engaging. I felt like I learned an enormous amount about Demetri, Noah, Brian, and Rhys, and I have a feeling that the author has really thought out all of their backgrounds, relationships, and futures. I really hope she'll put some of that on paper someday--or even a sequel with different characters in the same universe (B&N seems to think this is "Cascade #1," which bodes well).The near-future setting was familiar enough to be comfortable, but with fantastic little hints of the more advanced tech of the society. These aspects of the setting felt like a fun bonus.The sex scenes are incredibly engaging; I never wanted to skip or skim through them, because each of them added something to the plot or to the emotional growth of the characters, as well as being hot. Even where the character's kinks might not be among the reader's interests, the author makes it effective by focusing on how much the characters love the action, rather than the action itself. I've read a lot of terrible or, at best, mediocre books in this genre. This one is neither, and it's absolutely worth a read.