Poul Anderson is one of the "greats" of SF so I looked forward to re-reading this novel. Somewhat to my surprise, I was unable to recall anything about it as I read it, but at least that meant I could enjoy it without knowing the outcome! First published in 1958, The Enemy Stars was slightly tidied-up by the author in the 1980s. I have the later version published by Baen in 1987, which comes with a short-story sequel The Ways of Love, first published in 1979.
It is slightly different from my expectations, in that it is primarily about people rather than the grand mind-stretching concepts more typical of the 1950s. The story is set in the twenty-third century. A long time before, a matter transmitter had been developed which enabled virtually instantaneous transmission between worlds. The catch was that a transceiver was needed at both ends, so one had to be carried out to each star system on board a conventional, sub-light-speed space ship. Since the voyages took decades if not centuries, the ships were crewed on a rotation basis using the on-board matter transceiver to change crews every month.
A disparate crew of four strangers, two from Earth, two from different colony planets (and all men), arrive on board the Southern Cross, a ship which had been travelling longer than any other. There are tensions from the start: the two Earthmen are from very different levels of a highly stratified and paternalistic society, ruled by a dictatorial world government. The colonials had their own agendas, as relationships between Earth and its colonies were fraught, with frequent rebellions.
The Southern Cross was diverted from its target to investigate a strange, dark sun. Disaster struck, leaving the ship without a functioning transceiver and with limited food supplies. The bulk of the story is concerned with how the crew cope with their situation as they struggle to re-establish communication in increasingly desperate circumstances. There is a sub-plot running in parallel back on Earth, concerning the difficult relationship between the wife of one of the crewmen and his father, and their very different views of space travel and settlement.
I won't say anything more about the plot, or anything at all about the short-story sequel, as that would mean revealing the surprising climax of the novel. In fact, try not to look at the cover of the Baen edition in advance, because the illustration is one of the biggest spoilers I've seen!
Compared with other novels from the classic era of SF, I found this one a tad claustrophobic. The focus is on tense human relationships in a situation which is very confined, both physically and plot-wise. Despite this, the characters never really came alive for me, possibly because all four are treated fairly equally (the viewpoint switches between them) and we never get to know, or empathise with, any of them very well. Not really my favourite kind of story, but all credit to the author for an early attempt at writing science fiction with a human face.