Howard Zinn chose to write this book because he felt that it was important to put an alternative view of history before the American people. Zinn felt that American history books tell the story of American history from one viewpoint only: that of the elites of society. He felt that they tell a triumphal story of American history in which the US is always the “good guy” and our society is constantly progressing.
Zinn, by contrast, felt that Americans, and American elites in particular, have not really been the good guys in our history. He feels that the American system has been biased in favor of the elites. He takes a Marxist point of view and argues that American elites have systematically worked to oppress the lower classes in various ways. He sees that oppression permeating our history and continuing into the present.
Because he saw this, he wanted to write a book that would, he hoped, bring about a revolution in American thought. He wanted a revolution that would involve
people beginning to take power from within the institutions. In the workplace, the workers would take power to control the conditions of their lives. It would be a democratic socialism.
His purpose in writing the book from the point of view that he did was to promote this sort of a revolution.