sentences:  Rin Tin Tin proved to be the studio's most important commercial asset until the introduction of sound.Screenwriter Darryl F. Zanuck produced several scripts for Rin Tin Tin vehicles and, during one year, wrote more than half of the studio's features.Between 1928 and 1933, Zanuck served as Jack Warner's right-hand man and executive producer, a position whose responsibilities included the day-to-day production of films.