At a time when star prominence was the single most important factor determining a film's box-office success, Zukor had cornered the market. In a 1918 popularity poll...the six top stars on the list—Mary Pickford, Marguerite Clark, Douglas Fairbanks, Harold Lockwood, William S. Hart, and Wallace Reid—were all under contract to Zukor.
Using this leverage, Paramount was able to insist that prospective exhibitors interested in, say, the Pickford films, acquire them in large blocks along with a quantity of less attractive titles. These block-booking arrangements typically included groups of from 13 to 52 or even 104 titles. Paramount salesmen offered a variety of different product lines, from the top-quality Artcraft releases of Pickford, Fairbanks, and Hart to the more modest Realart productions, in which stars such as Bebe Daniels were being developed. Because these films had not yet been produced, exhibitors were required to "buy blind" from a sketchy prospectus or campaign book.〔Koszarski (1994), pp. 71–72.〕