L.R. Hubbard’s “The End Is Not Yet” was serialized in the August, September, and October issues of Astounding Science Fiction. I’ve not yet actually read the story (!), which to the best of my knowledge is neither available in full-text format on the Internet, nor in published monograph format. Well, I do know that “Anne Von Steel”, “Connover Banks”, and “Jules Fabrecken” are among the story’s characters – a quick perusal of the story revealed that. In any event, I’m under the impression that the plot is based upon the protagonist’s (or, protagonists’) encounter with versions of himself from parallel worlds with, inevitably, different histories or “world-lines”.
The concept of parallel universes was brilliantly executed – in terms of writing, plot, and sheer literary “ooopmh” – by Fritz Leiber, Jr., in Destiny Times Three, which appeared in Astounding in March and April of 1945, and was subsequently included in Gnome Press’ 1952 Five Science Fiction Novels. Really – Leiber did a fantastic job.
As for the August, 1947 issue of Astounding, the cover was created by Hubert Rogers, identifiable in a hard-to-define way by the appearance and posture of the two men in the foreground. The presence of silhouettes of spear-armed men in the lower background, a devastated city, and two mushroom clouds in the background (is one rising over the New York Metropolitan area – uh-oh!) lend the scene an apocalyptic tone. Also interesting is the way that Rogers painted the central character in shades of brownish-orange, with a red book – is that a plot key, of some sort? – in the very center of the composition.
References
L. Ron Hubbard, at Wikipedia
L. Ron Hubbard, at Encyclopedia Brittanica
The End Is Not Yet, at Internet Speculative Fiction Database
Guide to Wild American Pulp Artists – Hubert Rogers, at Pulp Artists