The Great Automatic Grammatizator (published in the U.S. as The Umbrella Man and Other Stories)[1][2] is a collection of thirteen short stories written by British author Roald Dahl.

The stories were selected for teenagers from Dahl's adult works.

All the stories included were published elsewhere originally; their sources are noted below.

They generally end with unexpected plot twists.

Groff Conklin in 1954 called the short story "The Great Automatic Grammatizator" "an awe-inspiring fantasy-satire ... an unforgettable bit of biting nonsense".