The modern system of bookselling dates from soon after the introduction of printing. The earliest printers were also editors and booksellers; but being unable to sell every copy of the works they printed, they had agents at most of the seats of learning. Antony Koburger, who introduced the art of printing into Nuremberg in 1470. Coming between the publisher and the retail bookseller is the important distributing agency of the wholesale bookseller. It is to him that the retailer looks for his miscellaneous supplies, as it is simply impossible for him to stock one-half of the books published. In Paternoster Row, London, which has for over a hundred years been the centre of this industry, may be seen the collectors from the shops of the retail booksellers, busily engaged in obtaining the books ordered by the book-buying public. It is also through these agencies that the country bookseller obtains his miscellaneous supplies. At the leading house in this department of bookselling almost any book can be found, or information obtained concerning it. At one of these establishments over 1,000,000 books are constantly kept in stock. It is here that the publisher calls first on showing or "subscribing" a new book, a critical process, for by the number thus subscribed the fate of a book is sometimes determined. What may be termed the third partner in publishing and its ramification is the retail bookseller; and to protect his interests there was established in 1890 a London booksellers' society, which had for its object the restriction of discounts to 25%, and also to arrange prices generally and control all details connected with the trade. The society a few years afterwards widened its field of operations so as to include the whole of the United Kingdom, and its designation then became "The Associated Booksellers of Great Britain and Ireland." The trade in old or (as they are sometimes called) second-hand books is in a sense, no doubt, a higher class of business, requiring a knowledge of bibliography, while the transactions are with individual books rather than with numbers of copies. Occasionally dealers in this class of books replenish their stocks by purchasing remainders of books, which, having ceased from one cause or another to sell with the publisher, they offer to the public as bargains. The periodical trade grew up during the 19th century, and was in its infancy when the Penny Magazine, Chambers's Journal, and similar publications first appeared. The growth of this important part of the business was greatly promoted by the abolition of the newspaper stamp and of the duty upon paper, the introduction of attractive illustrations, and the facilities offered for purchasing books by installments.