_Not least of the problems of preparing such a book as this is the finding of photographs. The names of the photographers responsible for the plates (or in a few cases those who obtained photographs for me) are given in the list of plates. The material for the figures, mostly redrawn for this book by P. J. Darvall, came largely from books and drawings in the libraries of the Royal Institute of British Architects and the Victoria and Albert Museum, to whose authorities my thanks are due, as also for notable assistance of various other sorts. The co-operation of the National Buildings Record, which was generously ready to add to their so extensive files photographs newly taken for use in this book, deserves specific mention here. In certain other cases I am not quite sure whether photographs were taken especially for me or not, but I must express gratitude in this connexion also to Professor Frederick D. Nichols of the University of Virginia, to the Staatliche Landesbildstelle of Hamburg, to the Institut für Denkmalpflege of Schwerin, and to Professor Donald Egbert of Princeton University._ _The notes indicate a considerable number of the fellow scholars who have assisted me in one way or another. But I would like to mention more particularly the following, who were good enough to read chapters or sections covering matters of which they had expert knowledge: John Summerson, Dorothy Stroud, John Brandon-Jones, Fello Atkinson, Robin Middleton, Turpin Bannister, Winston Weisman, James Grady, William Jordy, and Reyner Banham, not to speak of the Editor of the Pelican History of Art, whose contribution in a field especially his own was naturally of the utmost value. Needless to say these friends bear no responsibility for what appears here, but the importance of their contribution will often be very apparent in the notes. Robert Rosenblum did a very large part of the work of gathering the bibliography, a notable service to the author of a book such as this, as well as checking innumerable note references._ _Finally I must mention Mary Elkington, whose intelligent typing of successive drafts of the manuscript made revision a pleasure._ _H. R. H._ _1958_ ------------------------------------------------------------------------ PREFACE TO THE SECOND EDITION