Books, not which afford us a cowering enjoyment, but in which each thought is of unusual daring; such as an idle man cannot read, and a timid one would not be entertained by, which even make us dangerous to existing institution — such call I good books. – Henry David Thoreau

I suggest that the only books that influence us are those for which we are ready, and which have gone a little farther down our particular path than we have yet got ourselves. – E.M. Forster, Two Cheers for Democracy, 1951