The preparation of this book has been a joint labor during the spare moments of the two authors, whose time has been occupied with subjects to which pearls are not wholly foreign—one as a gem expert, and the other in the fisheries branch of the American government. But for the views and expressions contained herein, they alone are personally responsible, and do not represent or speak for any interest whatever. For many years the writers have collected data on the subject of pearls, and have accumulated all the obtainable literature, not only the easily procurable books, but likewise manuscripts, copies of rare volumes, original edicts, and legislative enactments, thousands of newspaper clippings, and interesting illustrations, many of them unique, making probably the largest single collection of data in existence on this particular subject. It was deemed advisable to present the results of these studies and observations in one harmonious volume, rather than in two different publications. This publication is not a pioneer in an untrodden field. As may be seen from the appended bibliography, during the last two thousand years hundreds of persons have discussed pearls—mystically, historically, poetically, and learnedly. Among the older writers who stand out with special prominence in their respective periods are the encyclopedist Pliny, in the first century A.D.; Oviedo and Peter Martyr of the sixteenth century; the physician Anselmus De Boot, and that observant traveler and prince of jewelers, Tavernier, in the seventeenth century. It would be difficult to do justice to the many writers of the nineteenth century and of the present time; but probably most attention has been attracted by the writings of Hessling and Möbius of Germany; Kelaart, Streeter, Herdman, and Hornell of Great Britain; Filippi of Italy, and Seurat and Dubois of France. While the book is a joint work in the sense that each writer has contributed material to all of the chapters and has critically examined and approved the entire work, the senior author has more closely applied himself to the latter half of the text, covering antiquity values, commerce, wearing manipulation, treatment, famous collections, aboriginal use, and the illustrations, while the junior author has attended to the earlier half of the book, with reference to history, origin, sources, fisheries, culture, mystical properties, and the literature of the pearl.