The Syndicate's process for creating the Nancy Drew books consisted of creating a detailed plot outline, drafting a manuscript, and editing the manuscript. Edward Stratemeyer and his daughters Harriet Adams and Edna Stratemeyer Squier wrote most of the outlines for the original Nancy Drew series until 1979. Volume 30, "The Clue of the Velvet Mask" (1953), was outlined by Andrew Svenson. Usually, other writers wrote the manuscripts. Most of the early volumes were written by Mildred Wirt Benson. Other volumes were written by Walter Karig, George Waller, Jr., Margaret Scherf, Wilhelmina Rankin, Alma Sasse, Charles S. Strong, Iris Vinton, and Patricia Doll. Edward Stratemeyer edited the first three volumes, and Harriet Adams edited most subsequent volumes until her death in 1982. In 1959, the earlier titles were revised, largely by Adams. From the late 1950s until her death in 1982, Harriet Adams herself wrote the manuscripts for most of the books.