Anyone who's seen Mastering the Art of French Cooking knows that Julia worked with a co-author: Simone Beck. The two women had a smash on their hands, but all was not rosy:
When Julia and "Simca" wrote the first volume of MtAoFC, Child was the newly-taught American enthusiast, Beck the intuitive Frenchwoman. Doubtless it was this combination that led to the book's comprehensive and accessible feel. But as Julia's editor, Judith Jones, wrote in her memoir My Life in Food:
It became clear to me, in working so closely with Julia, that her relationship with Simca was growing more and more strained. How much Simca realized what a celebrity Julia had become is hard to determine...As Julia was becoming more and more confident and was looked to as an expert on everything French, Simca was more condescending and difficult. I was in Julia's Cambridge kitchen once when Volume II was just about completed, and a fat letter from Simca arrived. Julia started reading it aloud, doing a hilarious impression of the French hauteur (non, non, non, ce n'est pas francais), and finally she threw the letter on the floor and stamped on it. "I will not be treated like dog Tray any more," she cried. Paul cheered.
In this clip, from a 1971 episode of The French Chef, the tension's so thick you can cut it with a dull couteau.