London: Thornton Butterworth, Ltd., 1923-1931, 1923. ALL FIRST EDITIONS. 6 vols., 9-1/8" x 6-1/4", illustrated with maps (some fold-out) and charts, bound in 1/2 blue morocco, ribbed gilt decorated spines, top edges gilt, marbled pastedowns and endpapers, internally clean and bright, inner and outer hinges fine, head and foot of spines fine, a VERY GOOD set.