Chapter 5 is devoted to Brian Walton and the London Polyglot Bible. It shows how Walton’s work was not simply an erudite accumulation of information from print and manuscript sources, but rather took a precise stand in the debates concerning the Old Testament that swirled around the Protestant world of the early 1650s. It examines how this created problems for would-be collaborators elsewhere in Europe, how Walton justified his approach by presenting a novel synthesis in the work’s ‘Prolegomena’, and how the vernacular dispute between Walton and his most prominent opponent, John Owen, turned on how they justified their work in terms of contemporary Reformed scholarship.