For one who is not engaged in devotional service, reading all of the books is simply like licking the outside of the honey jar… If we can simply understand one book, or one sloka, then perfection is there. Lord Caitanya warned about reading too many books, although I see in America this is very popular to get volumes and volumes of books and not understand one.

(From Srila Prabhupada's letter to Pradyumna, February 17, 1968)