Wikipedia
As a writer with limited talent, I’ve come to depend upon my thesaurus for finding imaginative words. So I was interested to learn that today is the birthday of the man who started it all, Peter Mark Roget, who was born in London in 1779. According to The Writer’s Almanac (https://www.spreaker.com/show/the-writers-almanac?), Roget was a very talented man. He had a long career as a doctor, invented a slide rule that did complex mathematics, and he was a serious student of optics. In fact, his Wikipedia entry credits him with origin of the persistence of vision theory that is used to explain apparent motion in film and animation (https://en.wikipedia.org/wiki/Peter_Mark_Roget).
But he is most remembered (and revered by writers like me) for his favorite project — arranging words in categories. When he retired, he catalogued 15,000 words and published them as the Thesaurus of English Words and Phrases in 1852. It was a milestone in publishing; since then, Roget’s Thesaurus has never been out of print and now contains more than a quarter of a million words.