Knock-knock joke

The knock-knock joke is a type of audience-participatory joke cycle, typically ending with a pun. Knock-knock jokes are primarily seen as children's jokes, though there are exceptions.
The scenario is of a person knocking on the front door to a house. The teller of the joke says, "Knock, knock!"; the recipient responds, "Who's there?" The teller gives a name (such as "Noah"), a description (such as "Police"), or something that purports to be a name (such as "Needle"). The other person then responds by asking the caller's surname ("Noah who?" / "Police who?" / "Needle who?"), to which the joke-teller delivers a pun involving the name (" place I can spend the night?" / " let me in—it's cold out here!" / " help with the groceries!").
The formula of the joke is usually followed strictly, though there are cases where it is subverted.
History.
A possible source of the joke is William Shakespeare's "Macbeth"; first performed in 1606. In Act 2, Scene 3 the porter is very hungover from the previous night. During his monologue he uses "Knock, knock! Who's there" as a refrain while he is speaking:
Writing in the "Oakland Tribune", Merely McEvoy recalled a style of joke from around 1900 where a person would ask a question such as "Do you know Arthur?", the unsuspecting listener responding with "Arthur who?" and the joke teller answering "Arthurmometer!"
A variation of the format in the form of a children's game was described in 1929. In the game of Buff, a child with a stick thumps it on the ground, and the dialogue ensues:
In 1936, Bob Dunn authored the book "Knock Knock: Featuring Enoch Knox", and he is regarded by some as having invented the modern knock-knock joke.
In 1936, the standard knock-knock joke format was used in a newspaper advertisement. That joke was:
A 1936 Associated Press newspaper article said that "What's This?" had given way to "Knock Knock!" as a favorite parlor game. The article also said that "knock knock" seemed to be an outgrowth of making up sentences with difficult words, an old parlor favorite. A popular joke of 1936 was "Knock knock. Who's there? Edward Rex. Edward Rex who? the Coronation." Fred Allen's 30 December 1936 radio broadcast included a humorous wrapup of the year's least important events, including a supposed interview with the man who "invented a negative craze" on 1 April: "Ramrod Dank... the first man to coin a Knock Knock."
Popular culture.
"Knock knock" was the catchphrase of music hall performer Wee Georgie Wood, who was recorded in 1936 saying it in a radio play, but he simply used the words as a reference to his surname and did not use it as part of the well-known joke formula. The format was well known in the UK and US in the 1950s and 1960s before falling out of favor. It then enjoyed a renaissance after the jokes became a regular part of the badinage on "Rowan & Martin's Laugh-In".