Our friend A at CERN has told us about the various distinguished visitors they receive, many of them household names in the scientific community. But, she said, you surprisingly often discover that they have gone weird in their old age. People who absolutely merited the Nobel Prize they received thirty years ago are now embarrassing themselves and their audiences by advocating fringe science.
Fred Hoyle was one of the very greatest astrophysicists of the twentieth century and made enormous contributions in at least half a dozen different areas. But this obscure book, based on a lecture he gave at the age of 78, almost literally made my toes curl. We learn that a giant comet, returning every 1600 years to harry the Earth, has ended the ice ages, taught mankind the arts of metal smelting, destroyed Sodom and Gomorrah, inspired several religions and the building of the Pyramids, caused the fall of the Roman Empire and the rise of Islam, and is due back in 2100. The leaps of logic are such that I suspected at several points that it had to be some kind of parody; alas, having reached the end, I fear it's not a joke.
I will at least say in Hoyle's defense that the people who claim he's ripping off Velikovsky are wrong. There are a few points of similarity, but Hoyle's story is just bizarre, far-fetched and poorly argued, not out-and-out lunacy. Unfortunately, I have trouble thinking of anything else positive that I can add to that.
If you want to check it out yourself, there's an online version here