On a Grander Scale: the outstanding career of Sir Christopher Wren, by Lisa Jardine

Jay Merrick assesses this leading light of Restoration England

Sir Christopher Wren's greatness is embodied in St Paul's cathedral, an architectural masterwork that took 40 years to complete. Lisa Jardine's new biography puts that stunning but singular achievement in a much richer perspective, and one that can only be properly experienced by going clubbing with "the chymical brothers". Wren's early, exceptional, brilliance did not guarantee an A-stream progress through life. Nor did his father's position as Register of the Order of the Garter, an "advantage" that in the late 1640s became a liability after Charles I was forced to go walkabout by Parliament. Courtly royalists such as the Wren family found themselves rudely straitened. But brilliance, like the stars that were Christopher's first and last loves, carries potent gravity.

It is this gravity that Jardine explores, to place Wren in the stellar context of other great minds – notably of Wadham College, Oxford – with which he traded ideas from an early age. His success depended not just on original polymathic thinking but carefully engineered patronage – and personal charm. When, at 17, he wrote to Charles Louis, the Elector Palatine, about his precocious discoveries, his faultless politesse was obvious. To the gizmo-susceptible Elector he presented "that Devotion towards your Highness, which I conceived while yet a Child, when you were pleased to honour my father's House by your presence for some Weeks".

Rather Blackadder-ish, that. So, too, is Jardine's occasionally over-zealous quotation from sources. Tracing Wren's mysterious movements during a visit to the Continent, she suggests he may have travelled to Villa Klarenbeeck in Holland. We are then subjected to two achingly dull poems about the place.

Fortunately, much of the painstaking research which drives this biography is not painful to the reader. But it is a mystery tour which effectively starts with the "littlenesses" given to the Elector (drawings of mites, a corn-drill and a "double-writing machine") and ends with the St Paul's saga. In between lies a complex tale whose keynote is survival; not only Wren's, but that of several monarchs, and of the pursuit of science at a crucial time.

This is what the title is all about. We learn as much – in some cases, more – about other scientific "virtuosi" and "club-men", and the braid of political machinations that entangled them, than we do about Wren; a bonus, this. Jardine has taken a considerable risk as far as a popular readership is concerned. Her multi-subject narrative moves backwards and forwards through time and place, not always in reader-friendly synchromesh.

However, the fastidious peruser will get a great deal from meticulously layered evidence, though Jardine's editors have let one or two repeated chunks through the net. For me, the extraordinary fact about Wren was his obscure route to architecture. By modern standards, he knew relatively little about the subject when appointed Surveyor to the King's Work in 1669. We can't even be sure what his pre-St Paul's architecture included as there is little clear evidence on whether his earliest commissions were built.

How did he learn to be an architect? By being so fearfully clever that he turned the mind that had made him Savillian Professor of Astronomy at Oxford to questions of structure and aesthetics.

In our age of nerdy specialisms, Wren's rapid progress reminds us that a fully inquisitive brilliance can grasp many subjects to a high level. His ability to understand architecture was based on science. He knew how perspective worked, in great detail. His geometric abilities meant he could examine drawings of Istanbul's Hagia Sophia mosque (which gave him the idea for St Paul's hemisphere within a dome) and know implicitly how the structural forces deployed themselves. So, too, did Robert Hooke, Wren's closest friend and a key figure in the network of scientists without whom Wren could not have blossomed so fully.

Once Wren got the Big Job, which included restoring 51 churches in the City damaged by the Great Fire, their work was often indivisible. Wren was the conceiver, Hooke the detail man, who designed experiments to find out if Wren's structural innovations would work.

Wren's triumphs were not concentrated in the design for St Paul's. His re-creation of St Stephen's Walbrook Church (bricks probably supplied by Daniel Defoe) is at least as surprising. But England's first Anglican cathedral, completed in 1711 when Wren was 79, is the rightful touchstone. And when Jardine gets down to its design, we are in a delightful wonderland of science and ambition, and a return to the aesthetic glories of Charles I's reign.

Jardine's marginalia turns up some nicely pointed surprises. Consider this chunk of Wren's proposal: "It will be a Shame to the Nation, which will be thrown upon us by all our Politer Neighbours, that haveing the Opportunity in our hands of makeing This Place the most convenient City for Trade in the World, we should negligently let it slide into Its old Barbarity." It could almost be Ken Livingstone wheedling for more London skyscrapers to make it a "world city".

Wren's ambitions were worldly, and other-worldly. Both St Paul's and the Monument had fascinating subtexts: the latter both a memorial to the Fire, and an experimental telescope; a section of St Paul's also had astronomical purposes. It was Jardine's discovery of the Monument's little-visited basement room – originally a secret laboratory – that triggered this biography.

Wren, still puzzling over cometary orbits and longitude at sea, died on 25 February 1723, believing that architecture held people together through infinite changes, and "aimed at eternity". Even in his late seventies, he was to be found making his way up the stairs within St Paul's great dome, small and frail, as he had been since youth – and still utterly inquisitive.

Fortunately, that visceral and breathtaking brush with eternity can still be experienced today. Jardine's rich mulligatawny of "littlenesses" will equip those equally inquisitive to go for that particular burn with righteous enthusiasm.

Lisa Jardine and Claire Tomalin will be appearing at the Cheltenham Festival on 13 and 11 October respectively