How many people did Mao kill?

From the Indpendent:

Mr Dikötter, who has been studying Chinese rural history from 1958 to 1962, when the nation was facing a famine, compared the systematic torture, brutality, starvation and killing of Chinese peasants to the Second World War in its magnitude. At least 45 million people were worked, starved or beaten to death in China over these four years; the worldwide death toll of the Second World War was 55 million.
....

His book, Mao's Great Famine; The Story of China's Most Devastating Catastrophe, reveals that while this is a part of history that has been "quite forgotten" in the official memory of the People's Republic of China, there was a "staggering degree of violence" that was, remarkably, carefully catalogued in Public Security Bureau reports, which featured among the provincial archives he studied. In them, he found that the members of the rural farming communities were seen by the Party merely as "digits", or a faceless workforce. For those who committed any acts of disobedience, however minor, the punishments were huge.

....

People were forced to work naked in the middle of winter; 80 per cent of all the villagers in one region of a quarter of a million Chinese were banned from the official canteen because they were too old or ill to be effective workers, so were deliberately starved to death. 

45 million is only the Great Leap Forward. How many others were killed in his consolidation of power and in the Cultural Revolution?

(Found via Legal Insurrection.)