"A Tough Guide to Fantasy Land" by Diana Wynne Jones.
This book is bloody brilliant! It looks like a parody style book but instead of just putting the boot into Tolkien instead it lists every possible fantasy novel cliche and describes them in terms of a travel guide to an imaginary world (naturally the map's at the front). Here's a few entries flipped to at random :-
Bread is quite well known in Fantasyland, but you will seldom get much of it and it will never be fresh. You might be given some to sop up some STEW in an INN of an evening, but in the morning, just as that day's baking should be ready, the Rules state that you will make a hurried departure, having time to grab up only a piece of stale loaf and a hunk of cheese.
Guards are the TOWN Watch and are quite useless. They always arrive too late to quell a TAVERN BRAWL or riot. This is because there are too few of them and all of them are stupid. Tourists will be glad of both of these facts at the point when they are trying to leave the town unseen.
Capital Letters at the beginnings of words are used liberally by the management according to Rules that transcend human understanding and may under no circumstances be questioned (see TABOO).