“The great thing is to be always reading but not to get bored – treat it not like work, more as a vice! Your book bill ought to be your biggest extravagance.”
From a letter dated April 8, 1941 to Derek Brewer from C.S. Lewis regarding the books he should read to prepare for his time at Oxford, where Lewis was to be his tutor.
Found in the Collected Letters of C.S. Lewis, Volume 3, in the supplement, page 1540-1541 in my hardcover copy. I first discovered the quote in Words to Live By: A Guide for the Merely Christian in the section on Books.