The De-evolution of Mankind (Pelican Books, 1975).

Many people are unaware that a young Donald Trump appeared on the cover of a book called The De-evolution of Mankind, published in Scarfolk by Pelican Books in 1975.

From the introduction:
"Scientists predict that, at some point in the early 21st century, humans will stop evolving and will start the process of de-evolution. Several signs will herald this decline:
i. People will stop reading books. It's estimated that the length of an average book will be eighteen words, including the title and copyright page.
ii. Increasingly, people will only vote for leaders who can communicate using an abbreviated, primitive dialect, a sort of "Dunce Patois" in which whole sentences will be reduced to single words: "True!", "Bad!", "Shame!", etc.
iii. The distinction between the real and the imaginary will be lost and fictional characters will ascend to the highest posts of office.
iv. Human hands will shrink through inactivity and will become little more than tiny, feeble scoops [...]

[...] The mighty space stations we once imagined in our future will drift unpopulated because the knowledge required to reach them will have been either outlawed or carelessly forgotten. The threadbare remnants of mankind will scrabble around a dying earth, daubing themselves with orange mud to avoid being burned due to the global overheating they said would never happen. We will return to this development in Chapter 4, which is entitled 'Consummate Dickheads'."