I would say that Howard Zinn's A People's History is the worst kind of history that can be written. He started with a premise that he wished to prove (the "the people" have been the systematic victims of the ruling class) and he strung together all the pieces he could find, usually using secondary material (how else could you write a 500-year history, really?), to make his argument, without any regard for the nuances of historicism (i.e., he presents conflicts from the point of view of modern sensibilities, without accounting for the sensibilities of the era(s) under investigation).
I read most of the book, but I stopped at the section on the Korean War, in which Zinn cites MacArthur's incursion into North Korea which drew in the Chinese military as evidence that Democratic and Republican presidents (Truman being president at the time) were both alike in their imperialism. I don't care if the point was correct or not -- but Zinn glossed over the fact that Truman recalled MacArthur and that historians look at this as one of the prime examples of the struggle between civilian and military power in the United States, and one in which the civilian government clearly won. To bring this up would have complicated his argument, so he chose (and he actively chose to do this, as this is very common knowledge) to misinform his audience rather than contend with the nuances of history.
As he states himself in the afterword of later editions of the book, "I had no illusions about 'objectivity,' if that meant avoiding a point of view. I knew that a historian (or a journalist, or anyone telling a story) was forced to choose, out of an infinite number of facts, what to present, what to omit . . . I wanted, in writing this book, to awaken a greater consciousness of class conflict, racial injustice, sexual inequality, and national arrogance."^1 His book is a polemic, and it would never have been published by an academic press.
With all that being said, his book reveals much about the darker side of American history that is not taught in primary or secondary schools in the United States. If that is the extent of your education on history, and you don't plan on reading much else anyway, then his book is a fine introduction to the "harsh realities" of the American past. There is absolutely nothing in his book, however, that is not covered in mainstream academic books and articles. Of course, you won't find an academic source that covers all 500 years of American history, and so you will spend a great deal of time sorting through material to find out all the information you want. Thus it is no surprise that his work remains so popular among disillusioned Americans who were taught as youngsters that the United States could do no wrong.
1. Zinn, Howard. A People's History of the United States, 1492-Present. New York: Harper Collins, 2007. <-- edition I cite
This is not meant to discourage new answers, but we do have a whole section of the FAQ dedicated to Zinn!
Not very. Readers of the History News Network voted A People's History of the United States one of the least credible books in print, alongside Killing Lincoln (Bill O'Reilly) and Gavin Menzies's appallingly shitty 1421.
The book is kind of accurate, but Zinn seems to care way more about the point he's trying to make than the real history of the American people. It's basically a big pile of elitist propaganda, but leftist propaganda instead of the rightist stuff you're used to from school. This makes it "revolutionary" in a technical sense, but revolutionary is not the same as true.
And that's the issue- Zinn cares more about indoctrinating students into radical leftism then he does about the truth, and this is made worse by how shitty faux-leftist college professors will pretend that whatever indoctrinates people into radical leftism might as well be the truth, because history is all subjective. Real assholes, the lot of them.
Dissent did a good leftist perspective on the book, and the Washington Post details much of his omissions and biases.
It's worth locating Zinn within the historiographical tradition of American Progressivism. Beginning in the late 19th century, a number of professional American historians (e.g., Frederick Jackson Turner, Carl Becker, Charles Beard) used social-scientific methods, as well as a rigorous reading of archival sources, to place the study of American history on a more "scientific" basis.
These historians have been labelled "Progressives" because they had an ideological affinity with the political movement of the same name. The Progressives were reformers who were concerned by the social upheavals of industrializing America, especially with the concentration of power in the hands of corporations and political parties.
An important part of their agenda was hem in the power of "interests" - particularly corporations who were driven strictly by the profit motive - and to return authority to the public, particularly in the form of government regulations that would break up trusts and protect the poor.
Progressive historians tended to see American history in this light: it was a continuous struggle between the "people" and the "interests", in which the interests would try to consolidate their power by corrupting the political system, while the people would use democratic methods - protests, reform movements, popular agitation - to uphold the public good.
Zinn was writing very much in this tradition, updated to reflect the social struggles of the 1960s: the Civil Rights and anti-war movements. His history is one in which elites are always venal and self-interested, and constantly in struggle with "the people", particularly poor and marginalized groups.
Does this necessarily make his work "inaccurate"? Not necessarily. All historians, whether they admit it or not, work within a particular narrative and intellectual framework - it's impossible to write a history that doesn't have a particular bias or point of view.
That being said, you should understand that there are other intellectual traditions to choose from: positivism, Marxism, the Annales school, poststructuralism, Whig history, and so on. So enjoy the eye-opening aspects of his book, but be aware that it's possible to interpret the same events in a very different fashion.
I read it when I already had a lot of knowledge about American history. I knew the good and the bad. Zinn had pathological need to put the worst spin on everything. He really has nothing nice to say. It's heavy handed Soviet ago-prop. Don't take my word for it. See what the vast majority of reputable historians have to say. Anybody pushing it is either selling something or is pretty naive.
I wouldn't let the right wingers on this sub scare you off. The book is uncomfortable and that's probably why they're so scared of it. Facts are facts and you can learn a lot from that book that is verifiable fact.