"I want to make sure we have exhausted every possible means of getting Olivia de Havilland," David O. Selznick wrote on August 1, 1939, about casting the role of Mrs. de Winter in Rebecca (1940). In a letter to Daniel O'Shea, his chief aide, Selznick elaborated on the complexities of bringing about such a result: 1) Warner Bros. might not allow de Havilland to do it, 2) de Havilland was committed to film Raffles (1939) for Sam Goldwyn, and 3) Leland Hayward was de Havilland's agent at the time his wife, Margaret Sullavan, was being considered for Mrs. de Winter. Writes Selznick, "I don't think [Hayward] will do much about de Havilland while Sullavan is in the running, and if we spoke to him now about de Havilland he might think we were kidding about Sullavan." Another complication was de Havilland's hesitation about going after a role that her sister, Joan Fontaine, was up for. In all, more than 20 actress were tested for Mrs. de Winter. Laurence Olivier was selected as Maxim de Winter and pushed hard for Selznick to cast then-girlfriend Viven Leigh in the part.
Here are screen tests of Fontaine—who eventually won the role—and four of the actresses she was competing against. Comments are by David O. Selznick and taken from Rudy Behlmer's book, Memo from David O. Selznick.
"Most of the people in the studio who haven't studied the picture on its casting...were more enthusiastic about Margaret Sullavan than anyone else...Apparently, her voice and her personality are so appealing that they don't stop to think that there is practically not one scene in the picture the qualities of which would not be affected by casting Sullavan. Imagine Margaret Sullavan being pushed around by Mrs. Danvers, right up to the point of suicide! Imagine Margaret Sullavan wishing she were a woman of thirty in a long black dress!!"
"I feel Loretta Young is a very good bet, and that with a few good pictures, she is the logical successor to Joan Crawford—but we don't think she is right for Rebecca."
"[Vivien Leigh] doesn't seem at all right as to sincerety or age or innocence or any of the other factors which are essential to the story coming off at all...I am convinced that we would be better off making this picture with a girl who had no personality whatsoever and who was a bad actress but was right in type than we would be to cast it with Vivien."
"I had pretty well decided to forget [Joan Fontaine] for the role since I could't get anybody on the studio staff, excepting only Hal Kern, or anybody in the New York office, to agree with me that she was physically an ideal choice for the role and that, from a perfomance standpoint, she obviously (or, at least, so I thought) was the only one who seemed to know completely what the part was all about."
"I think [Anne Baxter] has more sincerety than Fontaine, and that she is much more touching, in the words of Cukor, in the scenes. I think she is a shade young, although it is entirely possible that this would turn into an advantage. She is ten times more difficult to photograph than Fontaine, and I think it is a little harder to understand Max de Winter marrying her than it would be for Fontaine."