In 1977 at the age of 58, Levi retired as a part-time consultant at the SIVA paint factory to devote himself full-time to writing. Like all his books, "La chiave a stella" (1978), published in the US in 1986 as "The Monkey Wrench" and in the UK in 1987 as "The Wrench," is difficult to categorize. Some reviews describe it as a collection of stories about work and workers told by a narrator who resembles Levi. Others have called it a novel, created by the linked stories and characters. Set in a Fiat-run company town in Russia called Togliattigrad, it portrays the engineer as a hero on whom others depend. The underlying philosophy is that pride in one's work is necessary for fulfillment. The engineer Faussone travels the world as an expert in erecting cranes and bridges. Left-wing critics said he did not describe the harsh working conditions on the assembly lines at Fiat. It brought Levi a wider audience in Italy. "The Wrench" won the Strega Prize in 1979. Most of the stories involve the solution of industrial problems by the use of troubleshooting skills; many stories come from the author's personal experience.