I've referenced Henry Bett lately, and that's because I've been reading his book Nursery Rhymes and Tales:Their Origin and History. (Out of print-the link here is to the one copy available on amazon, $153.81). From 1924, it can be a bit shocking to the modern reader in its non-P.C.-ness. For example, Henry Bett quotes an African man who was wondering what is the cause of various forces of nature. Bett claims, "This, of course, represents an unusual level of thought for a savage mind. It is a speculative and sceptical mood rather uncommon in an uncivilized race." Which is not only quite an untrue claim to begin with, but opposes his whole thesis, which is that myths and tales were ancient people's ways of trying to explain natural phenomenon. They wouldn't be trying to explain anything if they weren't first wondering how it came about.
Other than that, Bett has a very interesting book. He not only takes current (or, what was current in 1924) tales and rhymes, but has many related examples through different cultures, and then cites historical facts and customs that relate to the tales and rhymes as we know them today. He claims that our tales and rhymes are rooted in historical fact, which have evolved and become distorted over time. He talks about the practice of burying people alive in the foundations of a house or bridge to appease the devil as the source of the rhyme "London Bridge is Falling Down," (which may or may not have been the case, although there's no reason to think a person was specifically buried under London Bridge,and there are other guesses as to the meaning of the rhyme) as well as the custom of baking pies in such a way that live birds can actually fly out of it when cut, such as in "Sing a song of sixpence."
Most modern analysts of tales assume they hold symbolic meaning. Which is surely partly true, but we can't forget the tales are very much the products of the cultures from which they came. Bett talks about certain fairy tales I've already posted about, Little Red Riding Hood and Bluebeard. For more on the history of nursery rhymes, you can visit this site.