It comes from James Thurber’s short story The Secret Life of Walter Mitty, which was first published on 18 March 1939 in The New Yorker.
In the story, the mind-mannered Mitty, inspired by his mundane surroundings, in turn imagines himself as a US Navy pilot, a surgeon, an assassin, and a Royal Air Force pilot engaging in heroic and daring deeds.
它来自詹姆斯·瑟伯(James Thurber)的短篇小说《沃尔特·米蒂的秘密生活》(The Secret Life of Walter Mitty)，该书于1939年3月18日在《纽约客》(The New Yorker)上首次发表。
And following the same concept as John-a-dreams, nearly 250 years later the Victorians came up with Johnny Head-in-Air as a nickname for a man with"his head in the clouds", unconscious of his surroundings.
A 1711 quotation from The Spectator, a daily publication who described castle-builders as ‘One of that Species of Men… denominated Castle-Builders, who scorn to be beholden to the Earth for a Foundation.’