Master Flea: A Fairy-Tale in Seven Adventures of Two Friends is a humorous fairytale fantasy novel by E. T. A. Hoffmann first published in 1822. Set in the city of Frankfurt am Main, the novel follows the story of Peregrinus Tyss, who becomes entangled in the conflict between supernatural characters in bourgeois form over Dörtje Elverdink, in reality Princess Gamaheh of Famagusta.

Ernst Theodor Amadeus Hoffmann (24 January 1776 – 25 June 1822) was a German Romantic author of fantasy and Gothic horror, a jurist, composer, music critic and artist.

His stories form the basis of Jacques Offenbach's opera The Tales of Hoffmann, in which Hoffmann appears (heavily fictionalized) as the hero. He is also the author of the novella The Nutcracker and the Mouse King, on which Pyotr Ilyich Tchaikovsky's ballet The Nutcracker is based. The ballet Coppélia is based on two other stories that Hoffmann wrote, while Schumann's Kreisleriana is based on Hoffmann's character Johannes Kreisler.