Today, the 41 million immigrants in the United States represent 13.1 percent of the U.S. population. The U.S.-born children of immigrants, the second generation, represent another 37.1 million people, or 12 percent of the population. Thus, together the first and second generations account for one out of four members of the U.S. population. Whether they are successfully integrating is therefore a pressing and important question. Are new immigrants and their children being well integrated into American society, within and across generations? Do current policies and practices facilitate their integration? How is American society being transformed by the millions of immigrants who have arrived in recent decades. To answer these questions, this new report from the National Academies of Sciences, Engineering, and Medicine summarizes what we know about how immigrants and their descendants are integrating into American society in a range of areas such as education, occupations, health, and language.