The document is a short story by Roald Dahl. It was publicated for the first time in 1980 in a collection of short stories named « More Tales of the Unexpected ». Then, it was publicated a second time in another collection of thirty short stories named « The Great Automatic Grammatizator » also known as « The Umbrella Man and Other Stories », the name wasn't the same in the USA.
This collection « More Tales of the Unexpected » has been serialized and « The Umbrella Man » has been serialized too. This TV serie is called « Bizarre, bizarre » in France and it was broadcast on FR3.