Great piece on an amazing book. In a former life I worked at Macmillan Pubishing Company, who published this work after purchasing the old Bobbs-Merrill Publishing Company, and I handled requests to reprint recipes and other material from this work. Sometimes I'd get requests from obviously poor women who were copying recipes out of a library copy of the book and wanted permission to do so. The fact that these people were doing so (and writing to be) was sometimes heartbreaking. I guess it is OK to say so now, but I used to snag extra copies of the book and send them out to those people, usually anonymously.
Still have a copy of the 1975 edition of the book that I use all the time.