Nicholas van Rijn is a space trader. In this book we get three stories involving van Rijn and his crew. In the first and best of the tales his ship has been attacked by Adderkops (interstellar pirates), and are in serious trouble. Their ship needing repairs but being unable to reach the nearest planet where these can be affected when they encounter an alien ship.

Once aboard they find that this is an alien zoo ship and the crew have occupied one of the environment chambers and it is up to van Rijn and his crew to figure out which race is the crew and then how they can communicate with them.

Poul Anderson was a writer of a previous generation. I don't say this to excuse poor writing and plotting for this is not what you get in this book. It is merely that the author tells 3 stories in 144 pages. Also these are stories that are very much in the feeling of golden age sf.

Each of the three tales presents a simple idea, told in a straightforward easy to read style. If you like your sf in great big wedges 500 pages plus then this will not suit, but for any fan of golden age sf, this should be a pleasurable read.