From Canon and Culture:
Even fifty years after his death, evangelicals continue to look to C.S. Lewis for wisdom on a host of topics for four simple reasons. First, and most important, Lewis was a thoroughgoing Christian, describing himself as believing in Christianity as he believed in the sun, not only because he saw it, but because by it he saw everything else. Second, Lewis himself was an enormously gifted and creative thinker and communicator. Third, Lewis drew deeply from the most profound and substantive philosophers, poets and theologians in the Western tradition and beyond. Finally, Lewis attended to the most crucial and perennial of ideas and themes common to humanity. If we continue to look to him, it is not because he is infallible, but because he identified and addressed eternal realities and lasting earthly concerns.