I am just finishing up Nathan Platte's "Making Music in Selznick's Hollywood" which as expected features Max Steiner- absolutely fascinating. And one of the most remarkable aspects is that even in cases where one name is featured in the credits as Composer, usually at least 2 and often more composers worked on the film. Steiner was often working on one film for Selznick and another film for Warners simultaneously. And of course numerous orchestrators were involved. All of them were very talented and had astonishing facility. David O. Selznick was one of the first producers to take serious interest in the score to a film.