From 1956, he wrote audio dramas for children and children's poems together with Peter Hacks. In 1956, Krüss published the children's book "The Lighthouse on Lobster Cliffs" with the publishing house Friedrich Oetinger. He also travelled to Italy and Yugoslavia. The subsequently well-known picture book "Henriette", whose eponymous protagonist is an anthropomorphized steam locomotive-hauled train, and which started a small series of similar, related picture books, was first published in 1958. After a reading of "My Great Grandfather and I" (which won the Deutscher Jugendliteraturpreis in 1960) in the "Tagesschau" in 1960, he suddenly became very famous. In the same year he bought a house with garden in Gilching, Bavaria. In 1962, his arguably most famous book "Timm Thaler" was published. It would later be adapted into a TV miniseries in 1979 directed by Sigi Rothemund, which was also known as "The Boy Who Lost His Laugh" in the United Kingdom.