The human being is, as the term suggests, rooted in being, and yet our understanding of being seems to grow dimmer with every passing year. The storehouse of that knowledge is the Perennial Philosophy, a distillation of the wisdom contained within the world's religions. Do not confuse this with religion itself: we are talking about what religious traditions have had to say about metaphysics, among other topics. There was a tremendous amount of valuable work done in this area (and also some no-so-valuable work) prior to the advent of modern science, so it helps to identify some formal channels to it. To help you on this path, here are three serious, intelligent, and high-quality sources of information on the web:

Temenos Academy. Sponsored by Prince Charles, this is a great source of audio lecture tapes.

The Joseph Campbell Foundation. The active legacy of one of the great students of comparative religion.

Parabola. A leading journal on myth, tradition, and the search for meaning.