If you are an avid reader I highly recommend this essay. Schopenhauer is a bit of a misanthrope, but this read is full of quotes that have left me thinking.
"When we read, another person thinks for us: we merely repeat his mental process. It is the same as the pupil, in learning to write, following with his pen the lines that have been pencilled by the teacher. Accordingly, in reading, the work of thinking is, for the greater part, done for us. This is why we are consciously relieved when we turn to reading after being occupied with our own thoughts. But, in reading, our head is, however, really only the arena of some one else’s thoughts. And so it happens that the person who reads a great deal — that is to say, almost the whole day, and recreates himself by spending the intervals in thoughtless diversion, gradually loses the ability to think for himself; just as a man who is always riding at last forgets how to walk.
Such, however, is the case with many men of learning: they have read themselves stupid. For to read in every spare moment, and to read constantly, is more paralyzing to the mind than constant manual work, which, at any rate, allows one to follow one’s own thoughts."
"One can never read too little of bad, or too much of good books: bad books are intellectual poison; they destroy the mind."
"Any kind of important book should immediately be read twice, partly because one grasps the matter in its entirety the second time, and only really understands the beginning when the end is known; and partly because in reading it the second time one’s temper and mood are different, so that one gets another impression; it may be that one sees the matter in another light."
I really liked the last bit as I often reread books at different times but have never immediately reread a book.