Voltaire: A Life, By Ian Davidson

The statistics are astonishing. During his 84-year life, Voltaire wrote to about 1,500 different people and 15,284 of his letters survive: quite a source for a biographer whose starting point was the discovery that no biography of Voltaire had been published in English for 20 years and that there wasn't one in print.

Born in 1694 and living until 1778, by which time the French Revolution was only 11 years off, the "liberal, anecdotal, combative, sceptical, lively, episodic, disputatious" Voltaire was very much a portfolio man and extraordinarily productive, despite whingeing about poor health all his life. He was, for example, France's dominant playwright for 40 years, with a whole string of successful tragedies running at Comédie-Française, although none is performed today. Later, he built several "am-dram" theatres on his various estates.

As a young man, Voltaire lived for a while in England in the 1720s, mastering English at breathtaking speed, which led to Lettres Philosophiques, that entertaining book which purports to be about the English and their habits but is actually a not very veiled criticism of French ways, and which caused one of Voltaire's many fallings out with state and church authorities.

Then there was the well-documented spell in Prussia at Frederick the Great's court, his status ambivalent. Honoured guest or resident servant? Ian Davidson thinks Voltaire began as one and finished as the other before finally being allowed to leave, once Frederick had proved himself considerably less enlightened than Voltaire had thought. Davidson does not incline to the (revisionist?) modern view of Frederick as a misguided, "enlightened" pragmatist rather than a tyrant.

Famously, Voltaire took up the causes of Jean Calas, François-Joseph Monbailli, Chevalier de la Barre and several others. An admirer of "enlightened" English law, Voltaire objected strenuously to the Ancien Régime's practice of trials behind closed doors, without legal representation for the accused, leading to sentences of prolonged torture (such as being "broken on the wheel") before subjection to some hideously imaginative, agonising form of death penalty: "an arbitrary barbarity against human nature". Much of Voltaire's intelligent, entertaining anger about these cases beams through in Candide, his sparkling 1759 satirical novel. Although Voltaire: A Life is a biography, not a treatise on the causes of the Revolution, the latter permeates Davidson's book like a subtext.

Voltaire also, of course, worked as a quasi "jobbing journalist", writing commissioned articles for that cornerstone of Enlightenment thought (although it was a long time before he realised that he was part of a movement with the other "Philosophes"), the Encyclopédie with Diderot and D'Alembert.

Then – he eventually became very wealthy – there was his career as a local seigneur. Exiled from Paris for decades until almost the end of his life, Voltaire took up farm management with enthusiasm, discovered first-hand just how poor many peasants were and, somewhat paternalistically, made sure that "his" people had jobs and a reasonable standard of living. Later, at Ferney, he used skilled exiles from Geneva to establish a watch-making industry, which lasted into the 19th century.

Davidson is also good on his subject's complex relations with women. (Nothing in Voltaire's life was straightforward.) Many "affaires" and "liaisons" in youth were followed by nearly 20 stormy years living with Émilie du Châtelet and then many years living with his niece Mme Denis, whose true sexual relationship with her uncle was known only to a few intimates.

Voltaire: A Life is written in the crisp, incisive prose of a practised journalist (Davidson was the Financial Times' Paris correspondent for many years) rather than the waffling self-indulgence which bedevils too many biographies written by academics. His research is impressive, too. He read all those letters before he began and quotes from them extensively in this refreshing book which isn't afraid, occasionally, to draw its own conclusions against the grain of what has been written before. But it is Voltaire's irreverent voice which dominates. What entertaining company he must have been.