The film only covers the latter part of the novel. Elia Kazan later said he didn't like the first part of the book, which deals with the youth and marriage of the characters played by Raymond Massey and Jo Van Fleet. It would also have been unwieldy to adapt the multi-generational story. Around this same time, the director had been thinking about the importance of unity in a work of art, and reflected on screenwriter John Howard Lawson's notion that unity comes from the climax. Kazan decided to focus on only the final section of the novel, dealing with the conflict between Cal and his father and brother. He then had to approach the thin-skinned John Steinbeck gently and tactfully about making changes to the story. He also had to approach Steinbeck with his plan to bring in another writer to work on the adaptation with Kazan. The author genuinely liked and trusted Kazan and allowed him to proceed without interference.