When I was young (yes, quite some time back now), I had many books that I liked to re-read time and again. Anything by Doctor Seuss or Roald Dahl, the poems of Spike Milligan and the Willy The Kid annual by Leo Baxendale to name but a few. There was, however, one book that I was thoroughly obsessed with from the first day I got it. It told of a murky and slimy subterranean world where strange creatures went about their everyday business in a manner totally alien ourselves before occasionally surfacing into our world to spread fear and terror (but only because that's their job). It's called Fungus The Bogeyman by Raymond Briggs and it's utterly brilliant.
Briggs has produced some other fine work over the years - Father Christmas, a similar tale about a grumpy old fella who's just doing his job every December 24th and can't wait to get back to bed, and the haunting When The Wind Blows which follows an ordinary couple coping in the aftermath of a nuclear attack*. To my mind, though, Fungus is his masterwork. It's the sheer level of detail that has gone into creating this entire world that the bogeymen inhabit; from their own specific bogey words (which are translated in footnotes at the bottom of the panel or page) to the sheer wealth of detail about their lifestyle and habits.
It's a combination graphic novel and encyclopedia that leaves you totally immersed within their world. It also has nice little touches like a censored image and some censored dialogue with a note claiming that the publishers wished to avoid offending the sensibilities of more sensitive readers. In the end, though, it's simply a story of an everyday man doing his job to provide for the family he loves - they just all happen to be disgustingly slimy monsters.
If you haven't ever read it, I strongly urge you to hunt a copy down. You won't be disappointed.
* I was never really a big fan of The Snowman. There's something just a bit too twee about it. It's definitely the most saccharine of all his works.