Mark Twain
Known for his writing talents, he’s the reason we got The Adventures of Tom Sawyer and The Adventures of Huckleberry Finn to read in grade school. Although this books gave him a fair fortune to lay with, he wasn’t the smartest of businessmen.
He lost most of his fortune in failed inventions, including investing close to $300,000 ($6 Million in today’s dollars) on a product known as the Paige Compositor, which was supposed to be automated type-setting machine, but was error prone and kept on breaking. He lost everything, including his trademark wit, and died penniless at 59.