Rudy Behlmer (BELL-mur) is the editor of “Memo from David O. Selznick,” (Modern Library) a new collection of the producer’s private letters, telegrams and memos. The making of “Gone With the Wind” and other film classics are documented in this revealing look at the movie business in its early years. This book is part of a series of film books being reprinted by Martin Scorsese. Also in the “Modern Library: The Movies” series are “The Making of 2001: A Space Odyssey,” “Agee on Film” by James Agee, and “The Art of the Moving Picture,” by Vachel Lindsay.