Melillo narrates the stories of two centuries of biotic connections between Chile and California. From French explorer Lapérouse's 1786 introduction of a Chilean potato at the San Carlos Borromeo Mission (near Monterey, California) to the 1964 Chilean Plan de Desarrollo Frutícola (jointly developed by the University of California, the California State Department of Agriculture, and the Chilean government), Melillo documents numerous cases across more than two centuries in which individuals, plants, commerce, and political forces from Chile and California have interacted. The idea that these two places share deep historical connections rooted in their natural and human environments is at first about as improbable as the geography of Chile itself; yet Melillo makes the case with one example after another that Californians, Chileans, and their natural environments are shaped by each other in ways both intended and unintended. As he does so, he brings to bear a well-researched and forceful argument to scholarship challenging the idea that the United States was shaped almost exclusively by the Atlantic World and its own western expansion.

Gaining a broader and deeper understanding of the Pacific-origin forces that helped to shape the United States is one goal of the book. But Melillo's work can also claim a place on the shelves of historians of Latin America because it chronicles California's influences on Chile. These were at least as important, perhaps even more important, as connections in the reverse direction. Both places experienced environmental changes resulting from a variety of interactions, including economic systems exported from one to the other, the movement of people and plants, and the sharing of research. For example, the introduction into Chile of California's Monterey pine encouraged single-species silviculture and led to the development of large-scale, agro-forestry exports with a wide range of effects on the Mapuche people and Chile's native forests.

In his introduction, Melillo categorizes three forms of connections: displacements that have unidirectional impacts, exchanges that have effects on both the sender and receiver, and influences that are intentional efforts to transform. Following the introduction, there are five chapters on Chilean impacts on California, followed by four chapters focusing on the opposite direction. The chapters on California are primarily related to the Gold Rush, with the exception of the last one. Chapter 4, is a history of the effects of Chilean alfalfa and sodium nitrate in the creation of the dairy and citrus industries, respectively. During the Gold Rush, Chilean wheat fed the state, its technology and expertise made mining more efficient, and Chilean women catered to the demands of miners. Most of these connections are previously documented, although the detail presented here is extensive and provides a well-researched and lively discussion of cultural, political, and legal issues as well. It is not always clear, however, if the focus belongs on Chileans, or more broadly on Spanish-speaking Americans.

Part II looks at California's impacts on Chile, including the ambiguous legacy of Henry Meiggs. Meiggs fled San Francisco and his collapsing financial affairs for the anonymity of Chile, where he became a railroad and mining developer. Meiggs introduced the enganche system of debt peonage to secure and control a labor force, both in the nitrate mines of northern Chile and in railroad construction in both Chile and Peru.

In addition to his discussion on Monterey pine silviculture, Melillo discusses the good fortune of Chile's avoidance of phylloxera in its viniculture and finishes with a chapter on the role of the University of California and the untold story of the “Davis Boys” and their contributions to Chile's agro-export businesses. The story ends with a criticism of market-fundamentalist neoliberalism.

Some of the content will be new for any reader, while some may be already known. In either case, there is a wealth of detail in a lively narrative that will reward anyone interested in the last two centuries of Chilean or California history.