This study of the business of transatlantic migration between Europe and the United States combines elements of social history, economic history, and business history to analyze a complex historical development. It is a first book and sometimes resembles a revised dissertation, but it provides an enormous amount of useful information and interesting new perspectives on one of the largest mass migrations in human history.

Keeling starts by noting that the near absence of legal barriers to migration before 1914 makes the underlying processes easier to see. He argues that too little attention has been paid to how the physical organization of transoceanic travel shaped the volume and patterns of migration and he sets out to rectify that failure. One-third of all migrants to the United States (and its colonial-era predecessors) arrived in the fifteen years between 1900 and the closing of the Atlantic to free migration after 1914, and it was the growth of an enormous shipping business that made that possible. And it was this mass migration which made the growth of the transatlantic shipping business possible, so it is the intersection of commerce and migration that provides the focus of Keeling's study. Keeling argues that migration histories rarely try to take an overview of the entire process, and business histories rarely try to focus on all transatlantic passenger traffic rather than individual firms or the whole shipping industry. Combining these two overviews is what enables Keeling to provide new insights into what really happened, instead of the kinds of assumptions that have pervaded historical overviews up until now. And it is the ocean voyage which was the one universal in transatlantic migration, regardless of the ethnicity, place of origin, or destination of the migrants.

Any such overview has to start with the transport revolution of the late nineteenth and early twentieth centuries. Steam engines and steel-hulled ships cut travel times and increased safety reduced the risks and discomforts of migration, making real mass migration possible, and Keeling's close attention to ship conditions adds a great deal to what we already knew about the process – especially how it affected migrants and influenced decisions to emigrate. Contrary to the assumptions of previous researchers, Keeling shows that increasing numbers did not result from declining fares (in fact the fares increased), but from the declining risks associated with migration as potential emigrants acquired more and better sources of information (especially as more and more of them had friends and relatives who had already migrated and who had access to reliable and cheap transatlantic postal services). Travel became increasingly faster and safer, and chain migration meant that migrants could count on increasing help upon arrival in the US (he reports that 94 per cent of arrivals in this period reported that they were migrating to join a friend or relative already in the US). All this was magnified by the increasing opportunities provided by the rapidly expanding US labor market. While migration costs in terms of travel fares actually rose slightly over time, the high wage differentials between regions of emigration in Europe and the US meant that migration costs, including lost income while migrating, could usually be recouped in a few months of working in the US. So relocation costs were hardly any hindrance to transatlantic migration, despite the attention paid to them by previous historians. Keeling clearly demonstrates that the most crucial factor in the whole process was the voracious demand for labor, and especially unskilled labor, by American industry.

That being so, Keeling suggests that this turns the usual question of why so many people chose to emigrate on its head, and asks rather why many more people did not choose to do so. The growth of transatlantic migration in the late nineteenth and early twentieth centuries closely tracked the growth of population on both sides of the Atlantic and never matched the proportion relative to the receiving population reached in the 1850s. Keeling carefully examines barriers to migration, both perceived and real. The increasing safety of transatlantic travel did not obviate some very spectacular accidents that took hundreds of lives at a time. Third-class transatlantic travel (steerage) became less uncomfortable over time, but it was still an intimidating prospect. Then too, a significant proportion of migrants to the US experienced failure (or even disaster) for a variety of reasons, and the same information networks that led some potential migrants to decide to go led other potential migrants to conclude that the very real risks involved in making the move were too great for them to try it themselves. Keeling provides a thorough analysis of the rewards, risks, and strategies involved in migrating across the Atlantic Ocean, along with an analysis of how they changed over time. Here, as in the earlier discussion of the transportation revolution, Keeling extends his focus back to the middle and late nineteenth century – an extension that is essential to the success of his study.

The increasing numbers of migrants over the not-so-long run meant that, despite the sharp short-term decline during economic slow-downs in the US, it was more than worthwhile for the handful of shipping companies who dominated transatlantic travel to invest in bigger, faster, and more comfortable ships capable of handling this growth. Keeling's attention to strategies by migrants is thus paralleled by his attention to strategies by shipping companies – their competition, conferences, combinations, fare wars, and renewed efforts to manage competition in non-threatening ways. This portion of the book moves away from social history, but provides an essential basis for understanding it.

One of the perennial themes of US immigration history is that of moves to limit, control, or even halt immigration via government action, and Keeling devotes a lot of attention to this. He shows how American industry's demand for unfettered access to European labor pools – combined with the political interests of immigrant citizens in keeping the gates open for their friends and relatives back home – managed to sidetrack attempts to limit the numbers of immigrants into efforts to control their quality. And even then the increasingly strict prerequisites for admission resulted in only miniscule impediments – as almost all arrivals passed through their inspections successfully. Indeed, the most common result of a powerful push towards quantitative restrictions was the establishment of yet another commission to investigate the issue.

Keeling shows that even economic downturns helped to stabilize the business infrastructure of migration because large numbers of immigrants simply returned to Europe when they faced extended unemployment in the US – with returnees helping to compensate the shipping lines for the reduced traffic to the US. He shows that even without economic downturns, ease of travel meant that not only were there large numbers of migrants who had achieved their goals in the US and who returned home to enjoy the fruits of their success (an increasing proportion of migrants to the US in the early twentieth century), but that there was an increasing pattern of migrants returning to Europe and then repeating their migration one or more times. In the first years of the twentieth century 18 per cent of arrivals from northern Europe and 12 per cent of those from southern Europe reported that they had been in the US before and their proportion continued to increase over time.

Some of the material, such as that about return and repeat migration, may sound familiar in this summary form, but Keeling consistently introduces fresh material and insights that make even the most familiar sounding portions worth our careful consideration. There are no exciting narratives to be found here and his prose is hardly scintillating, but Keeling has produced a valuable book here that should be of interest to all migration historians and which belongs in everybody's research library.