Between the 1860s and the early 1920s, more than two million Jews moved from Eastern Europe to the United States while smaller groups moved to other destinations, such as Western Europe, Palestine, and South Africa. During and after the First World War hundreds of thousands of Jews were permanently displaced across Eastern Europe. Migration restrictions that were imposed after 1914, especially in the United States, prevented most from reaching safe havens, and an unknown but substantial number of Jews perished during the Holocaust-as they had been displaced in Eastern Europe years before they were deported to ghettos and killing sites. Even after the Holocaust, tens of thousands of Jewish survivors were stranded in permanent transit for many years.

Between Borders tells and contextualizes the stories of these Jewish migrants and refugees before and after the First World War. It explains how immigration laws in countries such as the United States influenced migration routes around the world. Using memoirs, letters, and accounts by investigative journalists and Jewish aid workers, Tobias Brinkmann sheds light on the experiences of individual migrants, some of whom laid the foundation for migration and refugee studies as a field of scholarship, even coining terms such as "displaced person," and contributing to its legal definition at the 1951 United Nations Refugee Convention. The stories of these migrants and refugees were used to propose a new future for the United States, reimagining it as a pluralistic society-one comprised of immigrants.