Was the author CS Lewis a racist?

He was not a racist. And I don't believe for a moment that he was a sectarian, as the other answerer believes. If he were, he would not have hung out with J.R.R. Tolkien, let along been longtime friends with Tolkien (a Roman Catholic). Yes, he was from Northern Ireland, but he was an Atheist until he became a Christian. In doing so, he became Anglican, and actually shared many Roman Catholic beliefs.