We could never afford to take overmuch thought for the outsides of books; we were too much interested in their insides.
 Theodore Roosevelt, Theodore Roosevelt; an Autobiography (1913). copy citation

Context

“On the other hand, I expect to find many friends who will turn naturally to some of the old or the new books of poetry or romance or history to which we of the household habitually turn. Let me add that ours is in no sense a collector's library. Each book was procured because some one of the family wished to read it. We could never afford to take overmuch thought for the outsides of books; we were too much interested in their insides. Now and then I am asked as to "what books a statesman should read," and my answer is, poetry and novels—including short stories under the head of novels. I don't mean that he should read only novels and modern poetry.” source