The senior author has had exceptionally favorable opportunities to examine the precious objects contained in the various imperial and royal treasuries. Through the courtesy of the late Count Sipuigine, Court Chamberlain, and of the late General Philamanoff, custodian of the Ourejena Palata, he was permitted to critically examine the Russian crown jewels in the Summer Palace on the Neva, and in the Palata in the Kremlin, at Moscow, he examined the crowns and jewels of all the early czars. Through the courtesy of Baron von Theile, he was permitted to inspect carefully and in detail the wonderful jewels of the Austrian crown, which are beautifully ordered and arranged. The English and Saxon crown jewels were also seen under favorable conditions which permitted detailed examination, and the jewel collections of almost all the principal museums of Europe and America were carefully studied. As regards the literature of the subject, the senior author has gathered together the largest known existing collection of works treating of pearls and precious stones. In covering so comprehensive a subject, many obligations have been incurred from individuals and officials, to whose courtesy and assistance is due much of the interest of this work. To list all of these is impossible, yet it would be ungrateful not to note the following: her Majesty Queen Margherita of Italy; his Royal Highness the Gaikwar of Baroda; to H. R. H. le Prince Ruprecht of Bavaria, of Munich; to the late Prince Sipuigine, then chamberlain of the Russian Imperial Appanages; to Sir Edward Robert Pearce Edgcumbe for data relative to fisheries of East Africa; Dr. H. C. Bumpus, director of the American Museum of Natural History, New York, for many courtesies in regard to materials and illustrations; Sir Caspar Purdon Clarke, director, Dr. Edward Robinson, assistant director, J. H. Buck, curator of Metal-work, and A. G. St. M. D’Hervilly, assistant curator of Paintings, all of the Metropolitan Museum of Art, for numerous courtesies; Archer M. Huntington, founder of the Hispanic Society and Museum in New York City; Dr. Bashford Dean, Prof. Friedrich Hirth, Chinese professor, Dr. Berthold Laufer, Prof. A. V. Williams Jackson, professor of Indo-Iranian languages, and Prof. M. H. Saville, all of Columbia University, New York City; J. Pierpont Morgan, for the right to publish the illustration of Ashburnham missal; Dr. W. Hayes Ward, Assyriologist; Dr. Charles S. Braddock, formerly Chief of Medical Inspection for the King of Siam; Robert Hoe, for the two plates of unique Persian illustrations from his manuscripts; Edmund Russell, for East Indian material; F. Cunliffe-Owen, the author of diplomatic subjects; Ten Broeck Morse; Walter Joslyn; Stansbury Hagar; Henri de Morgan, explorer; Dr. Nathaniel L. Britton, director New York Botanical Garden, J. H. Lawles, and Ludwig Stross, for many courtesies; Miss M. de Barril and Miss Belle da Costa Greene, all of New York; Dr. Stewart W.