This is actually a several year old book, but I've confirmed it's in print status.
Robert A. Heinlein was a prolific writer...and like most writers left unfinished work. We don't know why he never finished this novel, but his outline and notes were found in his desk. In 2003 long term Heinlein fan Spider Robinson (best known for Callahan's Cross Time Saloon was hired to finish it).
Posthumous collaborations don't often work very well. This one does - the choice of Robinson to do the job was excellent, given some strong similarities in voice between the two writers. The book is set not in Heinlein's fairly well known "Lazarus" universe but in the world of Revolt in 2100 (which is one of the scariest future timelines ever written, especially when I look at some of the religious crazies who have way too much power these days). The protagonist is a young man - a little older than the norm for Heinlein's classic juveniles, but still falling into the category of protagonist Heinlein wrote the best.
And Robinson does a really brilliant job. The protagonist, after discovering that his girlfriend lied to him and is now expecting him to do stud duty and learn to be a high powered manager (he's a musician and composer) decides to storm out of the entire solar system and sign up to be a colonist. The book is...well...had Heinlein written it on his own, it would have been hard science fiction. But this is Robinson, and there are some things he can't resist. Starflight by meditation? That's classic Robinson. But the actual technology is classic Heinlein.
Here's the flaw.
Heinlein has two flaws in his writing. One is a tendency to stop the story to explain either his science of his sociology. The other is his...well known peccadillos about human sexuality and the way people fall in love.
Robinson has two flaws in his writing. One is his obsession with learning telepathy via zen meditation. The other is his obsession with music, which is only two steps below that of my late (and much missed) mother.
The book has all four. Now, to be fair, Robinson tones down the creepy sexuality and at least there's no dubious consent incest presented as a good thing. He also tries, tries, tries to leave what I assume is his own religion/philosophy out of it. But there's still the edges of both in there, and a lot of stopping the story to talk about music along with some stopping the story to talk about science. I have to admit it had me laughing at times. Also, if you haven't read Revolt in 2100 (which is somewhat obscure) you might want to get or borrow it and read it before this book, because a couple of references to events in it aren't really explained that well.
Despite the fact that it collects the flaws of both writers, it also collects their good points. I've decided not to do star ratings, but I'd recommend this to fans of either writer...and to people who like their space opera, which it really slides over the edge into in terms of its level of "hardness."