Short YA novel, a sequel to "the Star Dwellers". I found that I could read and enjoy this book without having read the first one, as there's enough backstory worked into it that new readers aren't left floundering. It's set in a relatively near future, not long after mankind has first developed an interstellar drive and made contact with other intelligent species. One of those species is an energy-based lifeform which has been around since the Big Bang, but which is nevertheless culturally compatible with humans. The Angels have sponsored humans for membership in another galactic culture, one that is short-lived by the standards of the Angels, but still remarkably long-lived and stable by human standards. So long-lived that even having the normal probationary membership period cut in half at the Angels' urging means waiting 50,000 years for full membership.

Naturally, some politicians are too impatient to wait. And so begins the mission to the Heart Stars, a journey to the heart of the empire to ask in person for immediate full membership. Along the way, the crew of the diplomatic mission ship see exactly how that peaceful, prosperous stability is achieved.

The book has a reasonable balance of engineering and social commentary. The science behind the faster-than-light drive is pseudo-science, but it's the sort that's extrapolated from real physics and internally consistent, not pure plot-devicium powered. It's a little too overtly preachy, but that's largely a result of it being a YA book written in the mid 60s. I'm not sure I'll keep it any longer, but it's a book I enjoyed enough that I've read it more than once. ( )

Less successful sequel to the YA novella "The Star Dwellers". Our Space Cadets journey to the center of the Galaxy to meet with the oldest humanoid aliens in the galaxy. Too much material covered in such a slim volume and a trifle preachy to boot. Together both volumes are worthy enough to be reprinted in an omnibus though. ( )

Run of the mill man meets alien fare. Sequel to The Star Dwellers. Equally wet. ( )