A year or three ago, in Edinburgh for the festival, I found myself in need of a sit down. The heat in Princes Street Gardens shimmered like the echo of a gong. I was not alone in feeling clobbered by sun and culture; most of the park benches were fully occupied. Eventually, I found a space between two youngish men, one seemingly asleep, the other absorbed in a newspaper. After a few peaceable minutes, the reader rolled up his paper, reached across me and swacked the sleeper on the head with it.

This initiated a violent argument, mostly consisting of surreal non sequiturs, in which I found myself embroiled as a clueless mediator. A small crowd gathered, not shocked but amused in a knowing sort of way. In a horrible lurching moment, I understood that I had fallen victim to dreaded street theatre – that instead of taking time out, I had been well and truly taken in.

As someone who never knowingly sits within reach of an actor, I was outraged by this abuse of public seating. For to sit down on a bench in a park or other public space is an act of non-participation. It makes a quiet declaration: "I've decided to do nothing for a bit. Not talk, maybe not even think. I'm in full view, so I'm not up to no good, obviously. I'm a harmless spectator of the passing world. Feel free to share this seat but don't start anything."

The very provision of benches by the council or the corporation acknowledges the human need to be private in public, to be conspicuously idle, to have nothing better to do. However, by taking a seat, one is made vulnerable – and not only to guerrilla thespians. Stories, imaginings, lurk in the shrubbery. That elderly gentleman over there polishing his specs on his tie, ostentatiously not listening to the vaguely foreign-looking fellow who's sharing his bench – isn't that George Smiley? Probably. Spies do love a park bench (I like to think that those S-shaped ones, shared by people facing in opposite directions, were designed by the Murmuring Department of MI6). Or the placid bloke you've sat down next to suddenly says: "My name is Forrest Gump. I'm an idiot. Let me tell you my story."

In my seaside town, there is a plethora of benches, each one bearing a little brass plate commemorating a deceased occupant. You sit with ghosts. You start to wonder about ex-Squadron Leader Gordon "Chuff" Robinson (1908-1983) "who loved this spot". Why did you, Gordon? What was re-enacted in the huge and shifting sky above Lyme Bay as you sat here? What's your story? And did you share it with Dorothy Cutler (1920-1994), who haunts the adjacent bench and who also loved this spot? Did you two perhaps flirt?

Benches and books have things in common beyond the fact that they're generally to do with sitting. Both are forms of public privacy, intimate spaces widely shared. The pleasing connection – physical and metaphorical – between book and bench has a history in public furniture. In fact, benches in the shape of books (and benches made of books) are nothing new. In Europe, as a three-dimensional witticism, they date back to the middle of the 18th century, at least. And they can be found in all sorts of places. In Istanbul, for example, you can park your bum on a 2m-long volume of Nâzim Hikmet Ran's verse while gazing across the Bosphorus. But the dozens of illustrated books as benches that have proliferated around London this week constitute a different thing altogether, and not merely in terms of scale and ambition.

As objects, they are, to my eye, beautiful: huge, opened and furled volumes painted by artists as diverse as Axel Scheffler, Lauren Child, Helen Oxenbury and Ralph Steadman. (There is something about Steadman's Alice Through the Looking-Glass bench, a chessboard distorted into a seat, that is itself deliciously Carrollesque.) They are also a campaign, one initiated by the National Literacy Trust in partnership with the public art outfit Wild in Art. While there is a Nineteen Eighty-Four bench, as well as others dedicated to Arthur Conan Doyle and Agatha Christie, the majority are inspired by children's books. Books About Town is a project aimed at getting children to read, an activity – we are repeatedly told – they do not do enough of. It comes in the wake of the dire rumblings of Ofsted's Michael Wilshaw directed at parents who fail to encourage their offspring's love of books by failing to read to them. Books About Town is the bright antithesis of dark warning and imprecation: a joyous celebration of the lovely oddity and richness of children's literature and (one hopes) an irresistible invitation to partake. It is also, in benchological terms, subversive. Here are public seats that loudly urge participation rather than withdrawal.

• Mal Peet is an award-winning children's author. His most recent novel is Life: An Exploded Diagram (Walker)

• For more information on Books about Town and to download the trail maps visit www.booksabouttown.org.uk