“Authors have a greater right than any copyright, though it is generally unacknowledged or disregarded. They have a right to the reader's civility. There are favorable hours for reading a book, as for writing it, and to these the author has a claim. Yet many people think that when they buy a book they buy with it the right to abuse the author.”

The Author As Reader, p. 259.
A History of Reading (1996)

1980s, GNU Manifesto (1985)

"Koheleth - the Man and his World" (1955), preface, p. vii

Source: How to Read a Book: The Classic Guide to Intelligent Reading

Metaphors of Reading, p. 168.
A History of Reading (1996)

Source: A Mathematical Theory of Systems Engineering (1967), p. v;

Preface to the 1913 edition
1890s, Quintessence Of Ibsenism (1891; 1913)
Context: I have never admitted the right of an elderly author to alter the work of a young author, even when the young author happens to be his former self. In the case of a work which is a mere exhibition of skill in conventional art, there may be some excuse for the delusion that the longer the artist works on it the nearer he will bring it to perfection. Yet even the victims of this delusion must see that there is an age limit to the process, and that though a man of forty-five may improve the workmanship of a man of thirty-five, it does not follow that a man of fifty-five can do the same.
When we come to creative art, to the living word of a man delivering a message to his own time, it is clear that any attempt to alter this later on is simply fraud and forgery. As I read the old Quintessence of Ibsenism I may find things that I see now at a different angle, or correlate with so many things then unnoted by me that they take on a different aspect. But though this may be a reason for writing another book, it is not a reason for altering an existing one.

On Lewis Carroll; p. 105.
"Confessions of a Caricaturist", vol. 1 (1901)