Henry Fowler (1858-1933) wrote A Dictionary of Modern English Usage after a career of pretty much nothing. He worked hard; he was honest and honorable, but he had never amounted to much: teacher, journalist, soldier (lying about his 57 years so he could fight), and editor.
But then, in 1925, he published the most popularly-acclaimed dictionary since Samuel Johnson's. It was a work that Joseph Epstein calls "one of a shelf of fifty or so great books written in English in the" twentieth century, noting:
It is immensely helpful, happily memorable, and endlessly rereadable [no sic]; it stands in a splendidly synecdochic relation to the culture that produced it: from the part that is this book one can infer the entire tradition of correctness, lucidity, and wit that once seemed emblematic of English intellectual life at its best.
The great work went through many editions, including a "concise" or "pocket" edition, becoming a mainstay in English grammar.
Ernest Gowers (1880-1966) enjoyed a high position in the British civil service, back in the days when a man had to be highly educated to attain such a position, not merely be recommended by a wealthy benefactor of your political party or recruited by a member of the deep state.
The British Treasury chose Gower to write a book about clean prose for public servants. The result was The Complete Plain Words, which was published for a general audience in April 1948 and sold 150,000 copies by Christmas 1948. It has since sold over 500,000 copies and has never gone out of print.
A full generation younger than Fowler, he later revised and updated the Dictionary, without supplanting the idiosyncratic great work that charmed throngs of people to buy it in the first place. His project was massive, taking him nine years . . . albeit probably slow-moving years, since he started at age 76 and finished at age 85 . . . and impressive enough that generations started referring to "Fowler and Gowers" in tandem.
Further reading: Joseph Epstein, "Messrs. Fowler & Gowers," Pertinent Players.