There once was a time...no, really...when Fforumites did this sort of thing.
Look at [
www.jasperfforde.com], there are some entries listed under "Guides to The Nextian Universe", that are the result of more or less collective work here on the fforum. (You know how this goes: one person (PSD, I think it was) does all the work, and everyone knows better.)
Each of these guides to the first four nextian books have an accompanying thread somewhere here...you'll have to dig deep to find them.
Another user (MartinB, longtime lost now) anounced he would compile something alike for The Big Over Easy. That was maybe six years ago. He never had anything to show, and since then noone has tried to do a guide that I know of.
For english nursery rhymes, I found [
www.rhymes.org.uk] to be pretty helpfull; [
www.nonsenselit.org] is a exhaustive resource on the poems of Edward Lear, and on Project Gutenberg you can find
Mary Steel's classical collection of english fairy tales.
The best tip for the newer books I think is to do the
sleuthing competitions that ran at the time of their publication. If you solve them (or at least read the solutions), you will be prodded onto a number of the more striking ideas hidden in the books.