Gargoyle
Gershon Legman was a folklorist who spacialised in sexual folklore and humour.
I think the work being referred to is 'The Horn Book' (wonderful title), but his better known work was the two-volume 'Rationale of the Dirty Joke' - particularly volume two, 'No Laughing Matter', which deals with the 'dirty, dirty joke'.
His masterwork was his edition of the Vance Randolph collection of "Unprintable" Ozark Folksongs and Folklore, vol 1, 'Roll me in Your Arms' folksongs and music) and vol. 2, 'Blow the Candle Out' (folk rhymes and other lore).
He did a similar job with the much-pirated The Limerick
A scholar who very much 'stood out' in his field of research, you might say.
Jim Carroll