Question: What was the first typewritten manuscript submitted for publication?
Answer: Life on the Mississippi (1883) by Mark Twain
Twain receives the credit for having dictated the book to a secretary, although this is not so much a verified fact as a claim found to be the most plausible case for first such use of the typewriter.
[Source - The Disappearing Spoon: and Other True Tales of Madness, Love, and the History of the World from the Periodic Table of Elements by Sam Kean]
Torching the Modern-Day Library of Alexandria
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