Few Americans have heard of Rabbi Haim Isaac Carigal, but every Yale University graduate has seen the evidence of his influence over the history of that institution. Because of Carigal's relationship with Yale's fifth president, Reverend Ezra Stiles, in 1777 Hebrew became a required course in the freshman curriculum. Many colonial-era American Christians had a respect for — even a fascination with —the Hebrew language and Jewish religion. In part, their interest stemmed from a belief that the Hebrew Bible, which they dubbed the "Old Testament," laid the ground for the Christian "New Testament." Educated American Christians, especially New England...