Henry D. Thoreau lived a life of simplicity, independence, magnanimity and trust;” in an “economy of living which is synonymous with philosophy;” in “the poverty that enjoys true wealth.” His literary creed was stoical, like his personal tastes. Reading, in his view, was, or ought to be, “a noble, intellectual exercise.” He did not wish to be lulled asleep; nor would he suffer his life to be taken by newspapers and novels. Perhaps his taste was narrow. He believed in books that call for alertness, books that a man must “stand on tiptoe to read:” books that deal with high themes simply; books “solidly done,” not “cursed with a style.”

I like that and especially the line - books that a man must "stand on tiptoe to read."