What insights into the workings of our public life do the biographies of these fifteen leaders provide? Did these very different men have anything in common that determined their success? The DCB/DBC biographies make it clear that although there is no standard mould that shapes Canadian prime ministers, prime ministerial success depends on both "character and circumstance." The biographies suggest that one of the only commonalities between the prime ministers was an unstable mixture of personal ambition and a sense of obligation toward their country and their political party. Pragmatism in making policy and in devising strategies of survival, rather than principle or ideology, often seems the guiding determinant in the success of Canada's federal political leaders. For a Canadian prime minister there is usually no higher ground than the claim to be the defender of national unity against threats of disruption and disintegration.