I’ve been on a bit of a Robert Silverberg kick in recent months and have generally enjoyed them. This novel is no exception. First published in 1961, this novel takes place in the 26th century after planet Earth (Terra) has developed instantaneous transport via “transmats” making colonization of additional planets much easier. Now, during Terra’s expansion into the galaxy, they’ve encountered an alien race which appears to be very closely matched to human evolution and level of technology and whom also happens to be in the midst of expanding into the galaxy.

This is essentially a first contact novel but also examines the nature of human-kind’s perceptions of their own place in the universe. What appears to be a friendly alien race turns out to be rather bossy and ultimately a third, extremely powerful alien race intercedes and forces the two “child” races to negotiate an equal solution and avoid armed conflict.

Unlike many “classic-era” science fiction stories, Silverberg tends to write very approachable stories rather than utilizing obtuse and overly-scientific prose. He does, however, convey an excellent competence in the nature of the science he uses, especially space travel and the reader comes away with a feeling that it is all entirely plausible. The overall novel was fun to read although the ending seemed a little bit like Silverberg wasn’t sure where to take it. It does conclude, but the major characters are left fundamentally changed but with no comments on what that would mean for them.

Early Silverberg. Read it as a teenager and again in my 20s and lapped it up both times. Makes me wish he'd stuck with sci fi. One of the best humans-and-aliens books I've ever read. If you can find it, buy it.

Very good science fiction novel starting with first contact by an Earth empire that's already settled many planets, with a similar alien galactic empire. Emissaries try to negotiate a treaty but on the way back they're lost--their FTL drive sends them to another galaxy. It's sort of episodic, with another plot development in the other galaxy. Reminded me of a couple Star Trek episodes (they also had transmats, like Star Trek's transporters), though it was written a few years earlier than that show; I really wouldn't be surprised if some of Star Trek's writer's had read this novel.
The only flaw I found was in how fast the emissaries were sent after first contact with no preparations whatsoever -- literally the next day.

Thorns is an unusual book. In some ways it has a good vision of the future except that this is happening around the turn of the millennium (2000?).
It kept my interest but it is not Silverbergs's best.