[2] In the epilogue, Koestler argues that the "divorce" between science and religion has certainly benefited scientific and technological development, allowing humanity to enjoy prosperity never seen before.

This is why Koestler openly contests the contemporary rejection of possible "non-causal interactions" and phenomena such as telepathy and extrasensory perceptions, to which he will return in his subsequent research.

"[4] The historian of astronomy Owen Gingerich, while acknowledging that Koestler's book contributed to his interest in the history of science, described it as "highly questionable" and criticized its treatment of historical figures as fictional.

[5] Gingerich said Koestler was wrong when he wrote that Copernicus's De revolutionibus was a "book that nobody had read" and "one of the greatest editorial failures of all time.

[6] Irish writer John Banville stated that the "original idea" of his Revolutions Trilogy came from his reading of The Sleepwalkers,[7] and also that Koestler deserves to be remembered also as a bridge between the two cultures.