Takaki writes that the Master Narrative of American History is a filter through which Americans see others. He states that "according to this powerful and popular yet inaccurate story, our country was settled by European immigrants, and Americans are white" (page 4). The Master Narrative causes Americans to see fellow Americans who aren't white as different and lesser than whites.
The author writes that this narrative, including its falsehoods, is deeply ingrained in the American psyche, though the reality of the country is very different. Many cities and the state of California are more non-white than white, and the history of our country is the history of immigration, not only from Europe but also from Asia, Africa, and Latin America. Takaki's book concentrates on the history of several groups in the US, including Black Americans, Native Americans, Asian Americans, Irish Americans, Jewish Americans, Mexican Americans, and Muslim Americans to give a complete picture of the diversity of our nation's history and its people.
The master narrative, or central argument, of A Different Mirror is revealed in the subtitle "A History of Multicultural America." As Takaki argues, "the established scholarship has tended to define America too narrowly." His central contention is that the concept of "American" needs to be expanded to include the rich patchwork of ethnicities and racial groups that have been as important to shaping American history as the white men that have dominated the historical literature until the last forty years or so. His methodology is making this argument is to compare the experiences of different peoples in American history. For example, he devotes chapters to enslaved and free African-Americans, Irish immigrants, and Chinese laborers, comparing and contrasting their struggles to carve out a place within American society. Crucial to his argument is the idea that race and ethnicity are social and historical constructions, contingent on a number of specific factors including economics, labor systems, and other things. Takaki argues convincingly that an honest reckoning with our multiethnic past is essential to grappling with a future in which the nation is becoming increasingly diverse.