For whatever this is worth: In Samuel Butler’s semi-autobiographical novel The Way of All Flesh, “one of the most eminent doctors in London” cures young Ernest Pontifex of nervous prostration by a course of “crossing,” or change. “Crossing is the great medical discovery of the age. Shake him out of himself by shaking something else into him”:

I have found the Zoological Gardens of service to many of my patients. I should prescribe for Mr Pontifex a course of the larger mammals. Don’t let him think he is taking them medicinally, but let him go to their house twice a week for a fortnight, and stay with the hippopotamus, the rhinoceros, and the elephants, till they begin to bore him. I find these beasts do my patients more good than any others. The monkeys are not a wide enough cross; they do not stimulate sufficiently. The larger carnivora are unsympathetic. The reptiles are worse than useless, and the marsupials are not much better. Birds again, except parrots, are not very beneficial; he may look at them now and again, but with the elephants and the pig tribe generally he should mix just now as freely as possible.

“Had the doctor been less eminent in his profession I should have doubted whether he was in earnest, but I knew him to be a man of business who would neither waste his own time nor that of his patients,” writes Butler’s narrator. “As soon as we were out of the house we took a cab to Regent’s Park, and spent a couple of hours in sauntering round the different houses. Perhaps it was on account of what the doctor had told me, but I certainly became aware of a feeling I had never experienced before. I mean that I was receiving an influx of new life, or deriving new ways of looking at life — which is the same thing — by the process. I found the doctor quite right in his estimate of the larger mammals as the ones which on the whole were most beneficial, and observed that Ernest, who had heard nothing of what the doctor had said to me, lingered instinctively in front of them. As for the elephants, especially the baby elephant, he seemed to be drinking in large draughts of their lives to the re-creation and regeneration of his own.

“We dined in the gardens, and I noticed with pleasure that Ernest’s appetite was already improved. Since this time, whenever I have been a little out of sorts myself I have at once gone up to Regent’s Park, and have invariably been benefited. I mention this here in the hope that some one or other of my readers may find the hint a useful one.”

Hence it is that the moral character of a man eminent in letters or in the fine arts is treated, often by contemporaries, almost always by posterity, with extraordinary tenderness. … These friendships are exposed to no danger from the occurrences by which other attachments are weakened or dissolved. … Plato is never sullen. Cervantes is never petulant. Demosthenes never comes unseasonably. Dante never stays too long. No difference of political opinion can alienate Cicero. No heresy can excite the horror of Bossuet. Nothing, then, can be more natural than that a person endowed with sensibility and imagination should entertain a respectful and affectionate feeling towards those great men with whose minds he holds daily communion.

— Thomas Macaulay, An Essay on Francis Bacon, 1837

In a 2014 blog post for the Wall Street Journal, mathematician Jordan Ellenberg examined the distribution of highlighted passages within Amazon Kindle books as an unscientific measure of how far the average reader progresses through each title before giving up. If the “popular highlights” are clustered densely near the start of a book, that’s (arguably) a sign that many readers abandon the book before reading much farther. Ellenberg gave these examples (each considering the location of the five most highlighted passages in the text):

Hard Choices, by Hillary Clinton, 1.9%
Capital in the Twenty-First Century, by Thomas Piketty, 2.4%
Infinite Jest, by David Foster Wallace, 6.4%
A Brief History of Time, by Stephen Hawking, 6.6%
Thinking, Fast and Slow, by Daniel Kahneman, 6.8%
Lean In, by Sheryl Sandberg, 12.3%
Flash Boys, by Michael Lewis, 21.7%
Fifty Shades of Grey, by E.L. James, 25.9%
The Great Gatsby, by F. Scott Fitzgerald, 28.3%
Catching Fire, by Suzanne Collins, 43.4%
The Goldfinch, by Donna Tartt, 98.5%

Ellenberg called the measure the Hawking Index, after physicist Stephen Hawking’s A Brief History of Time, which is often called “the most unread book of all time” … though it reaches only fourth place even on this short list.

“So take it easy on yourself, readers, if you don’t finish whatever edifying tome you picked out for vacation,” he wrote. “You’re far from alone.”

Inscribed on the Temple of Poseidon at Cape Sounion, southeast of Athens, is the name BYRON. Possibly the poet carved it during his first visit to Greece at age 22, before he became famous. He later wrote:

Place me on Sunium’s marbled steep,
Where nothing, save the waves and I,
May hear our mutual murmurs sweep …

But there’s no definite evidence that he carved it himself.

In 1998, Walter Hooper, literary advisor of the estate of C.S. Lewis, was asked to summarize the legacy of Lewis and J.R.R. Tolkien:

Above all, they were both aware that the type of books they were writing were the type of books they liked to read. As Lewis said on one occasion: ‘I wrote the sort of books I did because they were the sort of books I would have liked to have read when I was growing up.’ When Lewis came across The Hobbit when it was being written he was delighted. This was not only the sort of book he would have liked to have read, but also the sort of book he would like to write. …

They were very honest men. They were not writing to be avant garde. They were writing books that they liked. They, after all, had jobs which left them free so they weren’t depending on writing stories that would sell. In some respects, Tolkien was reluctant to send his work to a publisher so you can hardly call him ambitious for that type of success. They merely wrote the sort of books that they liked which turns out to be the sort of books that many other people like.

From Joseph Pearce, ed., Tolkien — A Celebration: Collected Writings on a Literary Legacy, 2001. Of Middle-earth, Tolkien wrote in a letter, “I had the sense of recording what was already ‘there,’ somewhere; not of ‘inventing.'”