John Hill Burton (1809-1881), The Book-Hunter etc.
(Edinburgh: William Blackwood & Sons, 1862), pp. 14-15:
It is a matter of extreme anxiety to his friends, and, if he have a well-constituted mind, of sad misgiving to himself, when the collector buys his first duplicate. It is like the first secret dram swallowed in the forenoon—the first pawning of the silver spoons—or any other terrible first step downwards you may please to liken it to. There is no hope for the patient after this. It rends at once the veil of decorum spun out of the flimsy sophisms by which he has been deceiving his friends, and partially deceiving himself, into the belief that his previous purchases were necessary, or, at all events, serviceable for professional and literary purposes. He now becomes shameless and hardened; and it is observable in the career of this class of unfortunates, that the first act of duplicity is immediately followed by an access of the disorder, and a reckless abandonment to its propensities.
Id. pp. 86-87 (quoting Richard Heber):
"Why, you see, sir, no man can comfortably do without three copies of a book. One he must have for a show copy, and he will probably keep it at his country-house; another he will require for his own use and reference; and unless he is inclined to part with this, which is very inconvenient, or risk the injury of his best copy, he must needs have a third at the service of his friends."
I am one of these shameless and hardened characters. For example, I have three copies of the "little Liddell," one for the study, one for the bedroom, and one for the living room. I need only one more, for the bathroom. Even if I don't need a duplicate of a favorite book, I sometimes buy one anyway if the price is right. I reckon I can give it a good home, where it will be appreciated and well cared for.