In the present edition (1893), which constitutes _the third edition_ of the “History of Architecture,” the editor has endeavoured to the best of his ability to follow the course which Mr. Fergusson himself adopted in publishing new editions, viz., to rewrite those portions which subsequent discoveries had proved to be either incorrect or doubtful. For instance, in Egyptian Architecture the accurate measurements of the pyramids made by Mr. Flinders Petrie, and his correction of Lepsius’s theories as regards the Labyrinth, have placed information at the editor’s disposal which was unknown to Mr. Fergusson. Corrections of this kind are inserted in the text. On the other hand, absolutely nothing new has appeared on Assyrian Architecture, and, therefore, Mr. Fergusson’s theories respecting the restoration of the Assyrian palaces have been retained; the tendency of the opinion of archæologists having, however, developed rather in the direction of vaulted roofs to the principal halls, footnotes have been appended giving the views of foreign archæologists on the subject, between which and Mr. Fergusson’s views the student is left to judge. In Persian work the accuracy of Mr. Fergusson’s views respecting the arrangement of the plans of the Persian palaces, which were first promulgated in 1855, has been confirmed by later explorations at Persepolis, Susa, and Pasargadæ, and footnotes giving the records of the same are appended. The results of recent discoveries in Greece and Italy have been recorded, sometimes in the text, sometimes in footnotes; and changes have been made in the chapter on Parthian and Sassanian Architecture, M. Dieulafoy’s photographs having enabled the editor to correct some of the woodcuts copied from Coste’s illustrations. Important changes have been made in the Second Part, devoted to Christian Architecture; the Byzantine style has been placed first, not only for chronological reasons as the first perfected Christian style, but from the impossibility of otherwise following the development of the Early Christian styles in Italy during the fifth and following centuries. The Romanesque, or Early Christian, style in Italy has been included in Book II., together with the later developments of style in that country; this has enabled the editor to bring the description of St. Mark’s, Venice, into the first chapter under Italy, to which chronologically it belongs, instead of placing it after the Pointed Italian Gothic style. The Italian Byzantine chapter has been omitted, and the two or three buildings described under it transferred to the Byzantine-Romanesque chapter. By the new arrangement it is possible now to follow almost chronologically the various phases of style in Italy.