One major problem with Cold War-era interplanetary space opera is that the solar system just isn't that interesting: no habitable environments to settle, no obviously valuable resources to exploit, no contentious native populations to clientelize. Harry Turtledove's 1988 novel
A World of Difference neatly alters this setting by replacing our small cold barren Mars with the much more Earth-like planet of Minerva. It stretches credulity that the first impact of a planet ten times as massive of our Mars on human history came when, in 1976, the landing
Viking spacecraft was attacked by a spear-wielding hexapodal native, and that the only impact this had on human history was the unfortunate premature death of Gorbachev in 1986. Further, as
this reviewer notes, Turtledove's Minervans are psychologically rather human-like despite their serious physiological, while the leaden dialogue of Turtledove's latest books has a clear genealogy in this, one of his earliest.
All these problems keep
A World of Difference from being anything more than a pleasant minor science-fiction novel, but it achieves the bare minimum nicely, with its the transposition of Cold War tensions into an alien civilization only partly understood. What legacies will historical materialism and late-modern capitalism leave on Minerva? Will females remain doomed to premature death in birthing? Can humans and Minervans be friends?
A World of Difference's answers may be obvious, but I liked reading each answer as it appeared. Not everything has to be at the level of Clarke or Asimov, after all.