Maggie Gram traces them to the trenches of the Western Front:
Because so many soldiers coming home from the First World War had been blinded by chlorine gas and mustard gas, noncongenital blindness suddenly became much more common in the United States. Congress responded to its newly blind constituents by putting aside some money for books in Braille. But Braille is not for everyone; it’s very hard to learn, and in the 1930s only one in four blind adults could read it. In 1935 the Works Project Administration began a project producing a special new phonograph machine called the Talking Book. The project operated out of a converted loft on Manhattan’s Tenth Avenue, and at its height it employed three hundred previously unemployed people. A sign at the head of the room said "Every man working here is doing his part to make the blind of the country happier." By the first months of 1937, ten thousand blind Americans were listening to WPA audio books.
The Dish 