This book has grown out of an earlier scheme. Originally undertaken as a contribution to the history of English Literature arranged under Authors, it came to be primarily or at least in an equal degree, a contribution to the history of English printing and bookselling. In the earlier years, as far as our first printer was concerned, it was not possible, except in unimportant details, to add to the information fully set out by Blades; and as far as Caxton's immediate successors were to be dealt with, all the materials were already in the hands of Mr Duff and the Bibliographical Society. It was equally needless to reprint, and impossible to check, all the statements of Herbert and Mr Arber. Nevertheless, in spite of my wish to keep it within the narrowest limits possible, the scope of the work grew; and the addresses of printers and publishers, as well as the description of devices and ornaments, were admitted into the text.

In making these changes, adopted after due deliberation, I regret that it was not possible to review my material throughout. Facts, which it was essential to codify, had been allowed to pass by. Perhaps it is truer to say, that only at the conclusion of my work did it begin to be apparent, on what lines research was desirable.

There were, and still are, enormous gaps in the University collection, which often render the assignment of books to their right typographical origin difficult or impossible.