Prince or pauper, it is never easy to assess the personality of anyone, rarely simple to discuss his impact on others and on events. Apparent certainties and promising clues dissolve under scrutiny; actions, words and writings turn out to be incomplete, ambiguous and misleading. As detective, the historian is rarely master of his subject, especially when he turns from the arid glibness of models to the problems of recreating the past and deals, as he should, with people, both individually and collectively, in their variety and complexity. There can have been few British statesmen who were as complex as William Pitt the Elder, First Earl of Chatham. Acclaimed, both in his lifetime and subsequently, as a great warleader, in what can be justly claimed as the first global war in which Britain was involved, indeed the great warleader until Churchill's apotheosis in World War Two, a peerless Patriot, the Great Commoner, a man of determination, integrity and vision; Pitt was also castigated by contemporaries and later historians as an arrant hypocrite, a man without balance or moderation, who would say anything to serve his purposes, a politician without honour. These failings have been variously ascribed, but generally blamed on temperamental and psychological faults.

The arrogance, egotism and overweening ambition that contemporaries denounced have been subsequently portrayed as facets of psychiatric illnesses, notably manic-depression. Pitt's imperiousness and extravagant behaviour and language were unbalanced.