Ars Technica:

If you’ve ever used a cellphone, hearing aid, or baby monitor, listened to live or recorded music, or recorded anything yourself, you’re indebted to James West.

West is the co-inventor of the electret microphone used in all of those devices and more. It’s estimated that over 90 percent of the microphones in use today are electret mics, and more than 2 billion of these devices are produced worldwide every year.

I’ve never heard of an electret microphone but this is a fascinating story.