Book excerpt: In this study, Thomas Leonard examines the history of relations between the United States and the countries of Central America. Placing those relations in their political, cultural, and economic contexts, he illuminates the role of such factors as the Clayton-Bulwer Treaty of 1850, William Walker's invasions of Nicaragua, Theodore Roosevelt's corollary to the Monroe Doctrine in 1904, the "Dollar Diplomacy" of the 1910s, and Ronald Reagan's support of the contra war. Central America and the United States is the fourth volume in The United States and the Americas, a series of books assessing relations between the United States and its neighbors to the south and north: Mexico, Central America, Cuba, the Dominican Republic, Haiti, Panama, Colombia, Venezuela, the Andean Republics (Peru, Ecuador, and Bolivia), Brazil, Uruguay and Paraguay, Argentina, Chile, and Canada. Lester D. Langley is the general editor of the series.