Complex sentence: In the 1960s, Zanuck became the president of 20th Century Fox; one year of his tenure, 1967, is chronicled in the John Gregory Dunne book "The Studio".
Split into simpler sentences: In the 1960s, Zanuck became the president of 20th Century Fox. One year of his tenure, 1967, is chronicled in the John Gregory Dunne book "The Studio".