Howard Zinn's approach to history was both unique and revolutionary. Historians before him focused on the supposedly great accomplishments of white men in American history, but Zinn argued that these men were not the true heroes of American history. Zinn strongly believed that the true heroes and heroines of America's great history were the ordinary people omitted from historical texts. Every chapter in A People's History tells the story of forgotten and oppressed people who struggled to build America.

The first chapter describes the meeting between Christopher Columbus and the Arawak Indians. The Indians gave the Spanish a hospitable welcome, but they were killed or enslaved by the greedy and merciless Spanish. The Arawaks were, according to Zinn, better people than their conquerors. Native Americans' suffering continued for centuries; in the nineteenth century, the US government disregarded the rights of Native Americans.

Zinn was a strong critic of late-nineteenth century American imperialism. Victims of that imperialism, such as the Cubans, were rarely mentioned by historians before Zinn. Historians preferred to write about Teddy Roosevelt's supposedly valiant charge instead. The wishes of both the Cubans and the Filipinos were ignored, and their freedom was denied. Later, a similar fate befell the Vietnamese.

Women and blacks were overlooked in traditional accounts of US history. Zinn wrote about their long and difficult struggle to achieve freedom and equality, and Zinn would argue that that struggle never ended.

In the late-nineteenth century, as the nation rapidly industrialized, ordinary workers were exploited. Some of them, including socialists, were brave enough to fight for better pay, safe working conditions, and more decent working hours.

Official history can be narrowly defined as history that is approved and endorsed by its subject, or the ruling power which controls its subject. Sima Qian's Records of the Grand Historian are an example of official history in precisely this sense, and so are most of the works of Procopius on buildings, wars, and so forth, the dullness and worthiness of which emphasize the unofficial nature of his Anecdota or Secret History by comparison. Both historians wrote their official works under the aegis of their respective emperors.

Almost everyone is left out of such histories, which tend to focus on the king or emperor, his immediate family, the rulers of neighboring countries, and a few politicians, courtiers and military officers. Even the great writers, artists and philosophers are excluded unless they happen to have royal patronage.

More broadly, official history might be taken as the history that, at any given time, is broadly accepted by and taught in the academy. This includes a far wider range of people than the officially-sanctioned histories, but still leaves out almost all of the working class, must of the middle class and all but a few exceptional women. Indeed, it can be argued that until Howard Zinn, few historians attempted to tell the story of ordinary people at all and even the great popular historians, Macaulay, for instance, provided principally a record of war and diplomacy, with biographical sketches of kings, ministers, generals, and practically no one else.

This question is an interesting one and brings up several questions itself. Firstly, what actually is history ? Secondly, what is official history ? Does it differ from unofficial history ?

Obviously what is deemed history depends on the values and mores of those writing or recording history. To indigenous Australians, for example, the notion of evolving from a hunting and gathering lifestyle to a more sedentary one was never regarded as a "measurable" step in history. To white European settlers, the lack of a settled population was  very important because it  meant that they were dealing with a seemingly "less evolved" race of people and so were almost justified in decimating it.

The writing of history has reflected society in the past. The roles of women and minorities has been ignored or simply devalued because their deeds have not been valued.

If we look at the study of the history of World War 2, the traditional historian has focused on the heroic deeds of the soldiers or indeed the horrific actions of our foes. The result is a text (written, spoken or viewed) that tells of the battles and sacrifices made. The contributions of minority groups is largely left ignored. Until recently, the role of women on the home front, the role of the American Indian and the part played by African Americans was only cited or studied in a minority of studies. The World War 2 museum in New Orleans has made the deliberate decision to focus on the part played by all these groups.

Another question to consider,of course, is what is reported. "Official" history is designed to tell the story of a country in an easy to read/understandable manner. It is important for a country to show itself in a good light. Sometimes, it is a case of what is left out of the history that is a concern. A particular examples we can use is the history of the settlement of the USA and the brave settlers who fought all obstacles to succeed. The reported mistreatment of indigenous Americans and their culture has received scant notice.