The 1960s represented the heyday of Delibes' literary career. The period was marked by the birth of his sixth son, Adolfo (later a graduate in biology) and a visit to Germany, where he visited several universities. The literary period opened with the publication of "Viejas historias de Castilla la Vieja" (Old Tales of Old Castile) in 1960, and" Por esos mundos" (In these worlds) in 1961. In 1962, Delibes published "Las ratas" (The Rats), one of his masterpieces. It constructs a story from a series of autobiographical anecdotes which evoke the rural environment of a Castilian village that has disappeared. The book won the "Premio de la Crítica" (Critics Award for Castilian fiction). In the same year Camino, the last of his seven children, would be born. Camino later graduated in Philosophy and Letters. Also in that year, the film version of "El camino", directed by Ana Mariscal, was shot. 1963 was a turbulent year: Delibes resigned on June 8 as director of "El Norte de Castilla" after several disagreements with Manuel Fraga, Minister of Information and Tourism. In 1964, he spent six months in the United States as a visiting professor in the Department of Foreign Languages and Literature of the University of Maryland. After his return, he wrote and published "Cinco horas con Mario" (Five Hours with Mario), which is considered his masterpiece. The novel is the monologue of a woman who holds a wake for her late husband while she recounts the memories of him. Other books published upon his return from the US included "USA y yo" (The United States and I) and "La milana". In the following years he visited Czechoslovakia and published "Parábola del náufrago" (literally: The Parable of the Castaway, translated into English as "The Hedge" by Frances M. Lopez-Morillas). Later in the 1970s, he followed up with several books about hunting, an activity about which he was passionate, and stories. Subsequently, he published "Un año de mi vida" (A Year of my Life), a personal diary.