Difficult as the subject of the Elzevir press is, that of the Aldine press is more so. It was established much earlier--_viz._, about 1489--and examples are more numerous and altogether more confusing. As a general rule they are also more expensive, and none but rich collectors can afford to compete for examples of the best class. Still, good specimens may occasionally be got for reasonable sums; and as a guide to the subject as a whole Renouard's _Annales de l'Imprimerie des Alde_ (1st ed., 2 vols., Paris, 1803; 2nd, 3 vols., _ib._, 1825; 3rd, 1 vol., _ib._, 1834) occupies a unique position. This work is arranged on a similar plan to the _Elzevier_ and is quite as indispensable to the specialist. An ordinary copy of the 2nd ed. will cost about 30s., but the more recent edition can sometimes be got for considerably less. Those fortunate persons who succeed in forming a good library of early printed books usually consult Dibdin's _Bibliotheca Spenceriana_, which professes to be nothing more than a descriptive catalogue of books of the 15th century in the incomparable collection of Earl Spencer. It is, however, full of notes by one of the best of English bibliographers. The British Museum _Catalogue of Early Printed Books in English_, 3 vols., 1884, which is carried down to 1640, and Maitland's _Early Printed Books in Lambeth Library_, 1843, carried down to 1600, are also frequently consulted. These works are of course supplementary to Lowndes' _Bibliographer's Manual_ and Watt's _Bibliotheca Britannica_, which, as previously explained, are on the shelves of every collector worthy the name, be he a specialist or not. The department of early printed books may, however, be left without further comment, as not one person out of many thousands is able for obvious reasons to devote his serious attention to it. Public libraries and similar institutions, which may be said to have a continuing existence, frequently contain a good show of works of this class, and, in the opinion of many, are the only suitable repositories for them. Privately printed books are those which are issued either from a private press or for the benefit of private friends. They are never published in the ordinary acceptation of that term, and cannot be bought at first hand. A good collection of these is of course difficult, though by no means impossible, to acquire; and for the benefit of those who may wish to devote themselves to this department--uninteresting as it undoubtedly is--Martin's _Privately Printed Books_ (1834, 2nd ed., 1854), in 1 vol. 8vo, is readily available. Many of these so-called "books" consist merely of single sheets of letterpress; others, on the contrary, are more pretentious. In the former case they are more correctly termed "broadsides"; and R. Lemon's _Catalogue of the Collection of Broadsides, in the possession of the Society of Antiquaries_ (8vo, 1866), though by no means a perfect book, is certainly the best that can be procured for our purpose.