In short, our gentleman became so caught up in reading that he spent his nights reading from dusk till dawn and his days reading from sunrise to suns… - Miguel de Cervantes

Finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind.

In short, our gentleman became so immersed in his reading that he spent whole nights from sundown to sunup and his days from dawn to dusk in poring over his books, until, finally, from so little sleeping and so much reading, his brain dried up and he went completely out of his mind. He filled his imagination with everything he had read, with enchantments, knightly encounters, battles, challenges, wounds, with tales of love and its torments, and all sorts of impossible things, and as a result had come to believe that all these fictitious happenings were true; they were more real to him than anything else in the world.

with little sleep and much reading his brains got so dry that he lost his wits.

And thus, from too little sleep and too much reading, his brain dried up and he completely lost his judgment.

...he spent whole days and nights over his books; and thus with little sleeping and much reading his brains dried up to such a degree that he lost the use of his reason.

he became so absorbed in his books that he spent his nights from sunset to sunrise, and his days from dawn to dark, poring over them; and what with little sleep and much reading his brains got so dry that he lost his wits.

In short, he became so absorbed in his books that he spent his nights from sunset to sunrise, and his days from dawn to dark, poring over them; and what with little sleep and much reading his brains got so dry that he lost his wits. His fancy grew full of what he used to read about in his books, enchantments, quarrels, battles, challenges, wounds, wooings, loves, agonies, and all sorts of impossible nonsense; and it so possessed his mind that the whole fabric of invention and fancy he read of was true, that to him no history in the world had more reality in it.

In short, our gentleman became so caught up in reading that he spent his nights reading from dusk till dawn and his days reading from sunrise to sunset, and so with too little sleep and too much reading his brains dried up, causing him to lose his mind.

"After he in his memory and imagination had made up, struck out, and discarded many names, now adding to and now subtracting from the list, he finally hit upon "Rocinante," a name that impressed him as being sonorous and at the same time indicative of what the steed had been when it was but a hack, whereas now it was nothing other than the first and foremost of all the hacks in the world."

Many people go looking for wool and come back shorn.

Silence spoke for the two lovers, and their eyes were the tongues that revealed their chaste and joyful thoughts.