(FORTUNE Small Business) – As rush hour descended on New York one evening in the early 1950s, Israel Myers, a Baltimore raincoat manufacturer, hurried to Penn Station to catch his train home. In his pocket, a crumpled napkin carried two scrawled words: "London Fog."

Izzy Myers needed a name for his new waterproof, washable, wrinkle-free coat. He didn't much like this one. Neither did his ad man. Neither, for that matter, did the sales rep who had just had the cocktail-hour epiphany. But Myers' new garment--which would be unlike any other in man's long quest for dry clothes--needed a name.

After several months the name grew on him, and Izzy did three things: He christened the coat "London Fog"; he fired the ad man; and he launched an incredibly durable brand that today, almost 50 years later and a galaxy away in fashion trends, remains an icon of style.

The story of Israel Myers and London Fog is a parable of entrepreneurial tenacity sensing a fashion hot button and hitting it full tilt. A tailor's son, Myers joined a men's clothing company in 1924 at age 17, after winning a state stenography contest. When the Depression nearly wiped out the company, Myers saved it by churning out rubberized trench coats for millions of World War II GIs.

But it was after the war that Myers hit his stride. The trench coat worn by Humphrey Bogart in Casablanca epitomized what had become a symbol of the "good war." But if it was sartorially cool, the heavy fabric or oilcloth was as hot as a sweatbox to wear. Myers tuned in to consumers' new lust for convenience and, in DuPont's eternal words, "better living through chemistry." Prowling a fabric mill, he had come across something new, a cloth of 50% cotton and 50% polyester. Forget it, said the mill owner; he'd have to retool his whole plant to make such fabric. But Myers found a more ambitious mill, called in chemists, and hurdled two years of problems. Lowell Abramson, a former exec, remembers one: The nicely crisp material was so stiff that the sewing machine needle, trying to get through it, created enough friction to melt the cloth. (Finally, Myers hit upon the idea of lubricating the fibers with oil.)

By 1954, when the coat made its debut at Saks Fifth Avenue, there was a new wrinkle: With an unpopular war in Korea, trench coats had lost their appeal. So the first "Fog" was a simple balmacaan; the trench came later. Myers made other contributions to civilization as we know it: a women's line, which sold out overnight, and the first zip-out lining, born of a long drive in a hot car. London Fog, along with chinos and Bass Weejuns, became part of the collegiate uniform. When young buyers faded away in the '60s, Izzy's son Jon Myers brought them back with TV ads--the first for a clothing maker. Soon, six of eight men's raincoats had "London Fog" inside the collar. As one ad had claimed, "When it pours, we reign."

After the family sold the business in 1976, London Fog Industries did not wear well. Now emerging from bankruptcy, the company can still capture top honors in brand awareness studies. But it seems stymied as to how to combine Bogie class with casual Friday. Israel Myers died this past December at age 93. If there's a napkin with an inspiration on it hidden somewhere, it will have to come from the pocket of another entrepreneur.