The full title in German (Momo oder Die seltsame Geschichte von den Zeit-Dieben und von dem Kind, das den Menschen die gestohlene Zeit zurückbrachte) translates to Momo, or the strange story of the time-thieves and the child who brought the stolen time back to the people.

has become a household phrase and Momo makes many friends, especially an honest, silent street-cleaner, Beppo, and a poetic, extroverted tour guide, Gigi (Guido in some translations).

This pleasant atmosphere is spoiled by the arrival of the Men in Grey, eventually revealed as a species of paranormal parasites stealing the time of humans.

Gradually, the sinister influence of the Men in Grey affects the whole city: life becomes sterile, devoid of all things considered time-wasting, like social activities, recreation, art, imagination, or sleeping.

After Master Hora stops time, but gives Momo a single hour-lily to carry with her, she has exactly one hour to defeat the Men in Grey in a frozen world where only they and she are still moving.

[1][2] It describes the personal and social losses produced by unnecessary consumption, and the danger to be driven by a hidden interest group with enough power to induce people into this life style.

[1][2] Robert N. Peck described that Momo has five principle elements: taking time, listening, imagining, persons and music.

[4] An article by philosopher David Loy and literature professor Linda Goodhew called Momo "one of the most remarkable novels of the late twentieth century".

Ende himself has said that "Momo is a tribute of gratitude to Italy and also a declaration of love,"[6] indicating that the author idealized the Italian way of life.

[9] Then Norwegian Prime Minister Thorbjørn Jagland, in his New Year Address to the nation on January 1, 1997, referenced Ende's book and its plot: "People are persuaded to save time by eliminating everything not useful.

Momo has been translated into various languages including Arabic, Asturian,[14] Bulgarian, Croatian, Catalan,[15] Chinese (Simplified), Chinese (Traditional), Czech, Danish, Dutch, English,[16] Estonian, Finnish, French, Galician, Greek, Hebrew, Hungarian, Icelandic,[17] Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Mongolian, Norwegian, Persian, Polish, Portuguese, Romanian, Russian, Serbian, Slovenian, Spanish,[18] Swedish, Turkish, Thai, Ukrainian, Vietnamese and Sinhalese.

The Spanish translation Momo, o la extraña historia de los ladrones del tiempo y la niña que devolvió el tiempo a los hombres was made by Susana Constante in 1978 for Ediciones Alfaguara: it was a great success in Spain and Latin America, having dozens of reprints since.

At the time of publication, it enjoyed great popularity in Iran, but due to the absence of any new printings since 1992, it is now inaccessible to the Iranian children.