His first book, "The Transformation of American Law, 1780-1860", was published in 1977, and is widely regarded as one of the most important books in modern American legal historiography. It won the Bancroft Prize, the preeminent prize in American history in the United States. A product of its time, this book sought to give a "thick description" (à la Clifford Geertz) of the transformation of American law in the period, without appealing to "covering laws" (à la Carl Gustav Hempel). The book was conceived as an attack on the so-called "Consensus School" of American Legal History, which had dominated the field of Legal History in the 1950s and minimized the role of class dimensions in American legal history. The main argument of his book is that in the first half of the 19th century, many judges self-consciously allied themselves with a rapidly growing class of mercantile capitalists and promoted a series of legal rules which favored those capitalists.