Mr. Fergusson’s first work dealing with the History of the Styles of Architecture was a large octavo volume, published in 1849, under the title of “An Historical Enquiry into the True Principles of Beauty in Art, more especially with reference to Architecture.” About one-third of the volume was devoted to an introduction, to which Mr. Fergusson attached so much importance that, in his preface he stated he considered it to be the text, and the rest of the work (viz., the description of the various styles) merely the illustration of what was there stated. The pith of this introduction was subsequently published in his later works, and a valuable chapter added to it on “Ethnography as Applied to Architecture.” The work contained only the history of the Early Styles from Egyptian to Roman, but it had been the intention of its author to treat of the Christian, Pagan, and Modern Styles of Architecture in subsequent volumes. This intention was never carried out, but the book formed the basis of another work published in 1855, entitled, “The Handbook of Architecture,” which included the history of the Indian, Chinese, Assyrian, Egyptian, Greek, Roman, Sassanian, and Saracenic Styles, in the first volume, and of Christian Art in the second. A second edition, a reprint only of this, appeared in 1859, and shortly afterwards, in 1862, a third volume was published, dealing with the History of the Modern Styles. On the revision and expansion of the work in 1873, this third volume became the fourth as hereinafter explained. In 1865 and 1867 the materials of the “Handbook” were rearranged to form an historical sequence, instead of a topographical one, and a new work was published under the title of the “History of Architecture”; the first part devoted to Ancient Architecture from Egyptian to Roman; the second to Christian; and the third part to Pagan Architecture, including Saracenic, Indian, Chinese, and Mexican. In 1874 a second edition of this work appeared (from which the whole of the Indian and Chinese sections were omitted and published separately in 1876 as a third volume, under the title of “Indian and Eastern Architecture”), and many additions were made to the Assyrian and Byzantine chapters.