Which nickname did 1920s racketeer Jack Diamond go by?

Which author's 1920 novel "Main Street" is set in the town of Gopher Prairie? Around 1920, Czech writer Karel Čapek popularized which word for a mechanical worker in his play "R.U.R."? Which Art Deco New York skyscraper, completed in 1930, is topped by a stainless-steel crown? In the 1920s, buses of Safety Motor Coach Lines of Muskegon, Michigan, were nicknamed which dogs for their color and sl… The 1920 comedy "The Saphead" was the first feature starring which stone-faced comic? Which author of "The War of the Worlds" also wrote the bestselling "The Outline of History" around 1920? Who was Chief Justice of the United States from 1921 to 1930? Which agency, created in 1921 by New York and New Jersey, has a Manhattan bus terminal named for it?