Process engraver and printer Emery Walker was a pivotal figure in the English, American, and continental European Private Press Movement from the 1880s until his death in 1933. This article looks at his theories for the typography, design, and production of books, and how those theories were developed by key designers and close associates of Walker such as William Morris, T. J. Cobden Sanderson, and Bruce Rogers and through the practical teaching of figures such as J. H. Mason and Edward Johnston. It examines how the theories were then taken up by the exponents of fine printing from the early 20th century through to the 1930s, focusing on the presses of Bernard Newdigate, Harry Kessler, Harold Curwen, and Francis Meynell. From these presses, and also via Stanley Morison and the Monotype Corporation, Walker’s theories are shown to have spread into mainstream book publishing in the first half of the 20th century. The article considers questions of whether the improvement in the readability of books in the early 20th century has had a continuing impact in book publishing, and makes suggestions how to access the incunabula referenced by the designers discussed, as well as collections of private press books and other early 20th-century fine printing.