This one looks like fun.
From the Boston Globe:
Without realizing it, any bleary-eyed parent who ever sang a Rolling Stones or Pearl Jam song to a fussy infant at 3 a.m. had an insight into the origins of many classical nursery rhymes.
At least that's one theory posited by London author, librarian, and tour guide Chris Roberts in the delightful new American edition of his book ''Heavy Words Lightly Thrown: The Reason Behind the Rhyme." A good number of nursery rhymes, he writes, began their existence as adult fare -- as bawdy tavern ditties or satirical political verse -- and only later became sanitized and child-friendly.
Of course, I already own the Annotated Mother Goose, but I firmly believe that you cannot own too many books about the history of nursery rhymes.