As the most sizable internal migration in U.S. history, the Great Migration has been the subject of a large literature measuring its causes, its economic consequences, and its legacy in terms of music and art, northern ghettos, poverty, and residential segregation. Although both black and white southerners migrated in large numbers between 1917 and 1970, black migration rates were larger and their destinations almost exclusively urban. Indeed, the patterns of black migration and subsequent occupational choice indicate a population fleeing agriculture for the industrializing North; upon arrival, the majority of black migrants found work as operatives or unskilled laborers and, even in 1930, fewer than 2 percent worked in agriculture.

Leah Platt Boustan's new volume is a critical addition to Great Migrations scholarship. Her focus is on the later and more intensive years of migration, between 1930 and 1970, and she breaks the literature's previous focus solely on the economic consequences for the migrant themselves. Indeed, Boustan's work spotlights how the in-migration affected labor market outcomes for black migrants, for northern blacks with whom these new migrants competed, and for white workers in the North whose livelihoods were less threatened by the incoming wave. In addition to these labor market analyses, her evaluation of the suburbanization effects of the migration wave represents a substantial contribution to the urban history of northern cities. For historians and economic historians interested in labor market disparities, urban/suburbanization, and African American economic history, Competition in the Promised Land should join other volumes in the National Bureau of Economic Research series on Long-Term Factors in Economic Development as a critical reference—one to be placed where it is easy to retrieve for repeated use.

Boustan's volume answers several distinct questions that many readers will find familiar. The book's analysis of the causal impact of black in-migration on suburbanization patterns in the North echoes many conclusions from her 2010 Quarterly Journal of Economics publication on the same topic. Black migration from the South famously followed distinctive geographic patterns: Mississippians to Chicago and Floridians to New York City, for example. Following the lead of the earliest migrants, subsequent migrants utilized their networks in northern cities to ease the costs of moving far from home with no housing, no employment and no established social network. Not only were migrant destinations patterned and predictable, migration origins were also predictable. Southern counties with greater reliance on cotton production and places with more extreme segregation and higher racial animosity sent more migrants to the North. In the opening chapter of this volume, Boustan establishes all of these facts for the 1940–1970 period. In doing so, she sets the stage to use “chain migration” patterns as an instrumental variable for migration to any particular northern city. This instrument then allows her to estimate the causal impact of arriving blacks on black out-migration from central cities.

Having established the relationship between black migration and white suburbanization, Boustan seeks to identify the cause of the calculated “white flight.” After putting forward a number of theories for the motivations for white flight, Boustan proposes a mechanism that operates through the funding of public goods: black migrants increased the heterogeneity of the central city population, bringing reduced property values in the city compared to suburban neighborhoods just a few blocks away. Boustan finds that the depressing effect of black in-migration on housing prices is entirely explained before 1970 by lower income levels that accompanied the new residents. But in the years after, these price differentials spiked along with desegregation efforts that would force school integration.

Black workers in the North experienced a substantial amount of occupational segregation from their white peers, experiencing far higher rates of employment as porters, janitors, cooks, and service workers than whites. Given this segregation, it seems reasonable to expect that the in-migration of southern blacks would serve to depress the wages of workers with whom they most directly competed: in other words, northern blacks. Indeed, Boustan finds that northern blacks experienced complete wage stagnation relative to northern whites between 1950 and 1965, in part because of the relentless influx of competing labor which served to depress black wages. White northerners, on the other hand, experienced only small reductions in wages as a result of the migration wave.

Finally, like many topics in American economic history, advances in longitudinal record linking have provided a catalyst for re-visiting some of the major questions regarding the Great Migration, including the returns to those who participated in the wave. And true to this literature, Boustan follows the tradition of others measuring the gains to inter-regional migration with new estimates of the gains from moving to the North by 1940. Her calculations, which are within-childhood-household estimates based on observations of brothers, indicate that migration to the North led to earnings gains of approximately 130 percent for black men, and that there was little selection into the Northern migrant stream. These results echo estimates of returns in other decades, including my own with William Collins for migration prior to 1930.

Perhaps the greatest value of this volume is to allow Boustan the space and liberty to connect the pieces of her previous work on these topics into a holistic view of the fortunes of black men in the North during the Great Migration, both new migrants and extant residents. The narrative license of the book brings out anecdotes and discussion heretofore hidden in her published articles, even as it buries (rightly) much of the technical detail that has given her work credibility in the past. One of the biggest payoffs of the narrative structure is that Boustan can bring in comparisons to other areas of her own expertise, including European immigration and Jewish migration, where comparisons to black internal migration are natural and informative. The drawback of this assembly, if there is one, is that the technically inclined reader will want more details. This is as it should be. The upshot is that the book will be useful reference material for scholars across the skill spectrum, more casual readers, and seasoned economic historians alike.