Botvinnik the Invincible was written in 1946, two years before Botvinnik won the World Chess Championship. The fact that it accurately predicts the ultimate victory by Botvinnink is itself significant.
Mikhail Moiseyevich Botvinnik was born on August 17, 1911. In 1931 at the age of 20 he won his first of six Soviet championships. He won the World Chess Championship in 1948 and held the title with two breaks until 1963. Botvinnik announced his retirement from chess in 1970.
Even after Botvinnik had lost the official world title to Tigran Petrosian in 1963, Bobby Fischer still regarded Botvinnik as the strongest player in the world (other than Fischer himself of course). I know this because I was with Fischer when he was talking to USCF Executive Director Edmund Edmondson while attempting to negotiate a match with Botvinnik for the World Chess Championship in 1970. Botvinnik had claimed that FIDE had acted unfairly when it had abolished the re-match provision prior to his match with Petrosian in 1963. Fischer apparently agreed, believing that Botvinnik would win if a rematch were held and thus was still the world champion, although unofficial.