Herbert Eugene Bolton (July 20, 1870 – January 30, 1953) was an American historian who pioneered the study of the Spanish-American borderlands and was a prominent authority on Spanish American history. He originated what became known as the Bolton Theory of the history of the Americas which holds that it is impossible to study the history of the United States in isolation from the histories of other American nations, and wrote or co-authored ninety-four works. A student of Frederick Jackson Turner, Bolton disagreed with his mentor's Frontier theory and argued that the history of the Americas is best understood by taking a holistic view and trying to understand the ways in which the different colonial and precolonial contexts have interacted to produce the modern United States. The height of his career was spent at the University of California, Berkeley where he served as chair of the history department for twenty-two years and is widely credited with making the renowned Bancroft Library the preeminent research center it is today.