J. T. Barclay gathered information for The City of the Great King while working as a missionary in Jerusalem. Published upon his return, this text became the standard authority on Jerusalem in England and the United States. His map of Jerusalem was considered to be the only reliable one at the time. Barclay offers observations on ancient, medieval, modern, and millennial Jerusalem, and includes 62 illustrations of various types including wood and steel engravings, illuminations, and lithographs.