Harvest of Empire discusses and analyzes the history of Latin American peoples, how they were influenced by outside forces during the colonial period, their relationship with the United States, and how Latin American immigrants have become an increasingly influential segment of the United States population. Writing about differences in racial attitudes between the Spanish colonies and Northern European colonies, González provides the complex “casta” system that classified people based on descent. For Spanish-descent peoples,

racial mixture was not allowed to subvert the class structure, though on occasion some of the elite “recognized” their mixed- race children . . . The arcane types of mixed-race offspring . . . were astounding. Beyond mestizos and mulatos, there were zambos (Indian and black), coyotes (mestizo and Indian), . . . and even more exotic distinctions.

Gonzalez explains how Latin American countries and cultures were colonized and dominated by European countries and, later, the United States. He uses this as the basis for his explanation of each culture and who they are today—as well as how they contribute to the United States.

Mexican labor. The Mexican market. Mexican music and food. Mexican television and radio. Mexican names of cities, states, rivers, and mountains. Anglo America continues to deny how much the social, cultural, political, and economic reality of the West and Southwest has been shaped by Mexicans. They have been part of its creation and they will form an even bigger part of its future.

Gonzalez discusses the lack of understanding that much of White America has about its own Latin American heritage. Many white Americans view Latin American immigrants as “foreign invaders” when they're really a part of the important cultural fabric of the country. He argues that it's important to recognize the influence of Latin American cultures, like Mexican culture, and the influences of the immigrants themselves on the United States.

Before the law could take effect, Ronald Reagan assumed the presidency and reasserted the fight against Central America's "Communists" as a linchpin of his foreign policy.

This is one of many quotes that illustrate how problematic the relationship between the United States and Latin American countries has historically been. Gonzalez goes on to explain that undocumented immigrants applying for asylum from Central America were held in detention facilities and that those places were soon overwhelmed. As more and more people fled violence and disenfranchisement, they flocked to the United States, becoming a large and increasingly influential population. 

As an American possession—belonging to the United States but not being a part of it—Puerto Rico has historically held a unique position in U.S. politics. Island residents are U.S. Citizens at birth, but they do not have the same rights and protections, nor the same responsibilities, as other Americans.

Gonzalez explains both the history of Puerto Rico–US relations and the current impact of that history on the United States. He goes on to discuss how Puerto Rican citizens don't have to pay taxes because they aren't allowed to vote in federal elections and the ways in which the United States lulls Puerto Ricans into accepting their own disenfranchisement.

In the twentieth century, Gonzalez contrasts the ethnic enclaves that became established earlier—such as his grandparents’ generation in New York—with later waves of immigrants, such as those fleeing Central American during the Contra wars.

By the time Central Americans arrived, the Latino immigrants of prior years had built stable ethnic enclaves, had perfected their English language skills, and even boasted an embryonic professional class with a basic grasp of its civil rights. The average Central American spoke no English,… was undocumented, unskilled, and desperate for any kind of work.

Despite the challenges they face, Gonzalez believes that Latin American immigration will continue to increase, because many conditions in Latin American countries are either unchanged or have worsened. Along with “the catastrophic economic crisis in Latin America,” another primary reason is that

Latino immigration is a movement of urban workers, not a rural movement of peasants . . .