I already have the second generation version (one published in 1971), but that one is a paperback, won't lie flat, and has got comparatively small print compared to the new one.
('Third generation' because the original was published in 1931. The 1971 edition was done by the original author's daughter, who added her name on the cover, and the 1999 edition was done by the daughter's son, who now has his name on the cover as well. My mother used to swear by it - presumably a first edition picked up in Canada.)