History of Jehovah's Witnesses book, "Three Worlds and the Harvest of This World", was published in early 1877. It articulated ideas that remained the teachings of Russell's associates for the next 40 years, many of which are still embraced by Jehovah's Witnesses: it identified a 2520-year-long era called "the Gentile Times", which would end in 1914, and broke from Adventist teachings by advancing Russell's concept of "restitution" — that all humankind since Adam would be resurrected to the earth and given the opportunity for eternal perfect human life. Russell claimed it was the first book to combine biblical end-time prophecies with the concept of
The Pyramid at the End of the World that had featured in the series. However, he went on to praise the ending of the episode and how it saved the episode itself, finding the similarities with the second part of the Tenth Doctor serial "The End of Time" and how the Doctor managed to save the world, but at a cost. Wilkins commenting on the unexpected ending, stating that it is "probably what I'm going to remember from "The Pyramid At The End Of The World," especially when thinking of it as the middle entry between the brilliant "Extremis" and the seriously intriguing-looking "The Lie Of The Land.""