The making of GYPSY is discussed at length in the book BROADWAY
SONG & STORY, edited by Otis L. Guernsey jr., copyright 1985 by
The Dramatists Guild, Inc. The book is basically the transcripts
of seminars sponsored by the Dramatists Guild. For GYPSY, the
moderator is Terrence McNally and the 3 participants are Arthur
Laurents, Stephen Sondheim, and Jule Styne. Jerome Robbins, director and choreographer of GYPSY, was not included on this panel and has this comment to make about its discussion: "Arthur
Laurents, during the WEST SIDE STORY symposium, called our discussion 'a sort of RASHOMON WEST SIDE STORY' and he also said, 'I don't think that's the way it happened.' Those remarks
summarize perfectly my own reaction to the GYPSY symposium."
The panel discusses the making of the musical as a true
collaborative effort. It is interesting and informative and you should try to find the book. I got my copy at the Dramatists Book Store which used to be on the 2nd floor of a building near the Winter Garden. I don't know if it's still there. Maybe you could look on Ebay, or the NY Public Library.
"Madam Rose...and her daughter...Gypsy!"