Jardine stresses that Wren, although diverted into a life of architecture, never abandoned his science. It is well known that Wren was a leading light in the early days of the research institute known as the Royal Society. No secret, either, that one of his most loyal assistants and friends was the scientist Robert Hooke, a man intellectually capable of challenging Newton on his own ground. Jardine, however, goes further than most in ferreting out the nature of the lifelong collaboration between the two men, both in scientific experiments and in the design of buildings. When designing St. Paul’s, Wren and Hooke made sure that the south-west clocktower could house an enormous vertical telescope - though in the end the idea proved impracticable. Jardine suggests that the way light filters through the outer and inner domes of the cathedral owes much to Hooke’s development of the microscope. Similarly Wren’s Monument to the Great Fire of 1666, a hollow column with a little-known laboratory in its basement, is itself a huge scientific optical instrument.

Late in life, Wren was to describe his architectural work as “rubbish” compared to the pursuit of science. Given the sublimity of his buildings in Oxford and Cambridge, at the Chelsea Hospital, at Greenwich and Hampton Court, at all those City churches as well as St. Paul’s, this may seem unduly self-critical. But this was the man who remained Professor of Astronomy at Oxford University long into his architectural career. Jardine, following the scientific trail, has constructed a book that is as much an account of a movement as a biography of a man. Scientists such as Hooke, Boyle, Flamsteed and Newton, the diarists and courtiers Evelyn and Pepys, Wren’s architectural protégée Nicholas Hawksmoor, his various academic mentors - all get much more than walk-on roles in this book. London was very small, the elite of the day was even smaller, a very few people operated the levers of power, and all of these people knew everybody else. It was an interdependent and claustrophobic society.

As Jardine tells it, Wren had two character foibles: total honesty, and a willingness to please. In the corrupt times in which he lived, these meant that he was exploited. While courtiers and financiers around him grew fat and lazy, the hyperactive, overworked Wren (a man small and quick, like his namesake bird) worked on endless public projects - whether the post-fire rebuilding of London or an abortive royal whim such as a palace in Winchester for Charles II - for which he was paid very little, and always very late. Some of his underlings at St. Paul’s earned as much as he did, despite his stature as Royal Surveyor.