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.

In a village of La Mancha, the name of which I have no desire to call to mind, there lived not long since one of those gentlemen that keep a lance in the lance-rack, an old buckler, a lean hack, and a greyhound for coursing. An olla of rather more beef than mutton, a salad on most nights, scraps on Saturdays, lentils on Fridays, and a pigeon or so extra on Sundays, made away with three-quarters of his income. The rest of it went in a doublet of fine cloth and velvet breeches and shoes to match for holidays, while on week-days he made a brave figure in his best homespun. He had in his house a housekeeper past forty, a niece under twenty, and a lad for the field and market-place, who used to saddle the hack as well as handle the bill-hook. The age of this gentleman of ours was bordering on fifty; he was of a hardy habit, spare, gaunt-featured, a very early riser and a great sportsman. They will have it his surname was Quixada or Quesada (for here there is some difference of opinion among the authors who write on the subject), although from reasonable conjectures it seems plain that he was called Quexana. This, however, is of but little importance to our tale; it will be enough not to stray a hair's breadth from the truth in the telling of it.

"…que hay dos maneras de hermosura: una del alma y otra del cuerpo; la del alma campea y se muestra en el entendimiento, en la honestidad, en el buen proceder, en la liberalidad y en la buena crianza, y todas estas partes caben y pueden estar en un hombre feo; y cuando se pone la mira en esta hermosura, y no en la del cuerpo, suele nacer el amor con ímpetu y con ventajas. Cervantes, Don Quioxte, Parte II, Capítulo LVIII
... y que tu posees a ambos, que quieren decir que mi amor por tu es doblado...
Yo, Sancho, bien veo que no soy hermoso, pero también conozco que no soy disforme; y bástale a un hombre de bien no ser monstruo para ser bien querido, como tenga los dotes del alma que te he dicho."

..."that there are two kinds of beauty, the one of the soul, and the other of the body; that of the soul is revealed fully through understanding, in virtue and honesty, in good living, in generosity and good breeding, all such qualities can be found to be in a homely man; and when such beauty, not the physical one, becomes the object of desire, then love only bears more impetus, focus, and exactitude of purpose."

From pro's and con's they fell to a warmer way of disputing.