With the bicentenary of Waterloo fast approaching in 2015, it seems a suitable time to reassess the lives and careers of the opposing generals, the Duke of Wellington and Napoleon Bonaparte. These two monster biographies each tell, incredibly, just half their subject’s story. Philip Dwyer’s Citizen Emperor climaxes at Waterloo and is the sequel to a much-praised first volume that covered Bonaparte’s rise from unknown junior artillery officer to effective ruler of France in under a decade. Rory Muir’s Wellington is the first volume of a two-part life that closes just short of the final seismic battle.

Born Arthur Wellesley (more accurately Wesley) in Ireland in 1769, the first Duke of Wellington is widely regarded as Britain’s finest soldier. There have been many attempts to chart and explain his rise to military greatness, most successfully by Elizabeth Longford, Paddy Griffith and Richard Holmes. But all these are now eclipsed by Muir’s monumental study, the fruit of more than three decades’ research, which is augmented by an online commentary on the sources and controversies of almost equal length. It is, in short, a life’s work and one of the finest military biographies to appear in years.

At almost every turn, in cool and judicious prose, Muir sifts through the conflicting evidence, correcting myth and error. Wellesley was born an aristocrat – his father was the first Earl of Mornington – but as a younger son he stood to inherit nothing and his place in the world