So Who Is John Galt, Anyway?: A Reader's Guide to Ayn Rand's "Atlas Shrugged"
Author's presentation: http://tracinskiletter.com/2019/09/26/so-who-is-john-galt-anyway/
Editions:
Paperback: https://www.amazon.com/gp/product/1694291782
Kindle: https://www.amazon.com/gp/product/B07YCY22W8
Craig Biddle has added two new parts to his TOS article, the original article is now Part One. Part Three is by Carl Barney except for a one sentence introduction by Biddle.
Part Two is like Part One but there are new details in Part Three.
(See at least his first couple of pages.)
An arguably repeated cycle in philosophy:
Rationalism, Skepticism, and Anti-Rationalism in Greek Philosophy after Aristotle --David Potts (1996)