The Varieties of Scientific Experience is a printed version of Carl Sagan's Gifford Lectures, originally presented in 1985. In them he discusses his views on religion, science, the search for extra-terrestrial life, and philosophy.
These are engaging, and quite possibly very useful to someone without a deep training in atheism. Sagan's sense of wonder at the natural world comes through, as does his openness to many things, even as he indirectly points out the problems and contradictions with much of modern religion.
A good read, particularly for those wondering about their religious faith.