The account is that unidentified scientists were conducting a study of macaque monkeys on the Japanese island of Kōjima in 1952. These scientists observed that some of these monkeys learned to wash sweet potatoes, and gradually this new behaviour spread through the younger generation of monkeys—in the usual fashion, through observation and repetition. (…) the researchers observed that once a critical number of monkeys was reached, i.e., the hundredth monkey, this previously learned behaviour instantly spread across the water to monkeys on nearby islands.
This story was further popularised by Ken Keyes Jr. with the publication of his book The Hundredth Monkey. Keyes’s book was about the devastating effects of nuclear war on the planet, presenting the hundredth monkey effect story as an inspirational parable, applying it to human society and the effecting of positive change. — Wikipedia (edited)
On the book cover, intense red clouds spread from a bright yellow island containing a blurb text using Helvetica. The book title and author name — both all lowercase — and the small print on the bottom use ITC Bauhaus.