Not long before he died, Sir Christopher Wren took a stroll down to the City to see how St Paul's was getting along. Turning the corner of Cheapside, he looked up at his masterpiece, and wept. Contrary to his design, a balustrade had been installed along the parapet of the cathedral; an utterly useless balustrade because no one would ever walk up there to admire it or need it to stop themselves falling off the roof.

‘Ladies think nothing well without an edging,’ he groaned.

This – the private life of buildings, how they develop beyond their original plans, how they are added to, bastardised and eroded – is Edward Hollis's subject. In this elegant, original book, Hollis starts off with the Parthenon,