There was a time when even old and unsaleable books had a commercial value. Before the cheapening of paper, a second-hand bookseller had always the paper-mill to fall back on, and the price then paid, L1 10s. per cwt., was one inducement to dispose of folios and quartos which remained year in and year out without a purchaser. The present price of waste-paper is half a crown a hundredweight, so that the bookseller is now practically shut out of this poor market. Indeed, an enterprising bibliopole was lately offering 'useful old books,' etc., at 3s. 6d. per cwt., free on the rails, provided not less than six hundredweight is bought. 'To young beginners,' he states, 'these lots are great bargains'; but whether he means young beginners in literature or young beginners in trade, is an open question. In either case, 'useful old books' at the price of waste-paper are a novelty. There is a certain amount of danger in the wholesale destruction of books, for posterity may place a high value, literary and commercial, on the very works which are now consigned to the paper-mill. Unfortunately, posterity will not pay booksellers' rent of to-day. Just as those books which have the largest circulation are likely to become the rarest, so do those which were at one time most commonly met with often, after the lapse of a few decades, become difficult to obtain. In one of his 'Echoes' notes, Mr. G. A. Sala tells us that, in the course of forty years' bookstall-hunting, he has known a great number of books once common become scarce and costly--_e.g._, Lawrence's 'Lectures on Man'; Walker's 'Analysis of Beauty'; Millingen's 'Curiosities of Medical Experience'; Beckford's 'Vathek' in French; Jeremy Bentham's works; and Harris's 'Hermes.' Possibly the disappearance of these and many other books may be attributed to certain definite causes. For example, in the early years of this century one of the commonest books at 1s. or 1s. 6d. was Theobald's 'Shakespeare Restored'; but fifty years later it was a very rare book. The interest in Shakespeare and his editors had become quite wide-spread in literary circles, and literature in any way bearing on the subject found ready purchasers.