Answer
The answer is Hemingway. Resnais collaborated with many notable authors throughout his career, including Marguerite Duras, Alain Robbe-Grillet, and Jorge Semprún, but he never worked with Ernest Hemingway. Hemingway's distinctive writing style and themes of masculinity, war, and loss did not align with Resnais's cinematic approach and preference for exploring psychological depth and social critique.