It is probably not worth worrying about spoilers over half a century after a book was published, but I’ll try to be sensitive nevertheless. Leif Svensen, our protagonist, finds himself in Asgard on the eve of Ragnarok. All the familiar Norse gods are there: Thor, Loki, Odin, and kith and kin. As they prepare for the battle with the frost giants, who, in the mythology win the contest, the deities are decidedly subdued. They believe their fate is sealed by a prophecy of defeat. Leif, being a true American, gives them a rousing speech about overcoming the old ways. Gods, by nature, are conservative. They don’t have to bow to tradition—they are gods, after all. The deities are not swayed by the logic of a mere mortal, even after his apotheosis. Fate, it seems, trumps even gods.
I’m pretty sure that Lester del Rey wasn’t attempting to make any profound theological observation here. One can be an accidental theologian. Ideas of gods and what they must do can be a detriment to their own future. Even with the evidence of the failure of their own prophecy, the gods can see no way forward other than that they’ve recognized as fate. They are, without saying too much, out-maneuvered by human resourcefulness. A man tames his god, and it can become a man’s best friend. I wasn’t expecting such theological insight from a sci-fi book from my youth. Then again, you never know what may happen when you come back to a book after leaving it on the shelf for four decades.