G is for Gumshoe

I've been re-enjoying the Kinsey Milhone series of late. Bill happened to spot the title of a recent read and asked me what was the meaning of 'gumshoe'. He knew how it is used, but why?

I couldn't answer off the top of my head, but the answer is that of course 'gumshoe' is a slang word for detective. In the early 20th century when 'sneakers/tennies/Plimsolls/trainers' came about, the soles were made of 'gum rubber'; this was also about the time of the 'Golden Age of Detective Fiction'. Gumshoes were silent, implying stealth, a critical skill of detectives, apparently.

If you've not discovered Sue Grafton's 'alphabet series', I can't recommend it highly enough.