Mind the step a photo by The original SimonB on Flickr.
I'm currently reading Underground England by Stephen Smith, a follow-up to his previous book based on the capital Underground London. Both take us below the streets and fields of every day life to see what lurks beneath in tunnels, vaults, burial chambers and so forth. They also both stretch their definitions somewhat by covering issues that are blatantly above ground or underwater, but could be classed as "underground" in the sense of hidden or clandestine.
While I have never wanted to join the pot-holing or caving fraternity, I don't object to wandering about with a few feet of rock or building above my head when the opportunity arises. I enjoy the Underground in London for the simple fact that it exists despite all the engineering challenges they faced to build it as well as for it being a reasonably effective way from getting from a to b. And I'm more than happy to wander around a "show cave" in the Peak District or Cheddar Gorge when the opportunity arises.
But as well as the obvious and accessible deepness, what both of these books offer is a glimpse into the support structure of our daily lives. Peering through the gaps in the floorboards and negotiating with disinterested beuracracy is just as interesting as what becomes revealed through these actions. We all know what we do in our own daily lives, and how those we come into contact with don't often appreciate the backstage stuff that gets them their loaf of bread, bus stop or X-ray. What Smith has done in these two tomes is illuminate a whole bunch of institutions that help keep us going and also happen to be "below stairs" - literally or metaphorically.
There are more academic works out there about what goes on beneath our feet (London Under London by Trench and Hillman being one I would also recommend) but as an introductory delve I'd say you can't go far wrong with these.
