There are two great divisions of the objects that attract collectors. In the first come all items of individual handiwork, where no two can be precisely alike (since replicas by the authors are too rare to destroy the argument), and each specimen cannot be duplicated. Into this class fall paintings and drawings of all sorts, gems, sword-guards, lacquer, and ivories, and a thousand other objects of art. In the second, where duplicates have been produced in large numbers, the collector has a new ideal--to complete a collection that contains examples of every variety of the subject, be they artistic:--coins, etchings, or engravings of any sort; natural objects:--butterflies, or crystals, or things which belong neither to nature nor art:--postage-stamps, the majority of book-plates, and other trifles so numerous that even a bare list might extend to pages. The first class demands a long purse, and has, of necessity, a certain failure confronting it, for many of the best specimens are already in national collections, and cannot by any chance come into the market. But in the second class, no matter how rare a specimen may be, there is always a hope, and in many cases not a forlorn one, that some day, in some likely or unlikely place, its fellow may be discovered. And the chance of picking up a treasure for a nominal price adds to the zest of the collector, whose real delight is in the chase, far more than in the capture. Who does not hope to find a twopenny box containing (as once they did) a first edition of Fitzgerald's _Omar Khayyám_? or a Rembrandt's _Three Trees_ in a first state? Or to discover a _Tetradrachm_ Syracuse, B.C. 317, 'with the superb head of Persephone and the spirited quadriga, on the obverse,' in some tray of old coins in a foreign market-place? Without more preamble, we may go on to the objects the new collector wishes to acquire; and to provide him with a hand-book that shall set him on the track of desirable specimens. This desultory gossip may also serve to explain indirectly the aims and limits of the present volume, which does not pretend to be a critical summary, not a history of art, and neither a treatise on engravers, nor an anecdotal record of artists, but merely a working book of reference, whatever importance it possesses being due only to the fine examples of the subject, which those concerned have most kindly permitted to be reproduced. It is quite true that in collecting, the first of the two classes demands more critical knowledge, because as it is not a collection but only a selection that is within the reach of any one owner, it follows that each item must reflect his taste and judgment. In the second division there is danger lest the rush for comprehensiveness may dull the critical faculty, until, by and by, the ugly and foolish rarity is treasured far more than the beautiful and artistic items which are not rare, and so fail to command high prices.