by Joseph Campbell
As to why, simply because - thou art that :)
This, IMO, is the most succinct and unpretentious book about "meaning" of scriptures.
Book description from Amazon:
Woven from Joseph Campbell s previously unpublished work, this volume explores Judeo-Christian symbols and metaphors and their misinterpretations with the famed mythologist's characteristic conversational warmth and accessible scholarship. Campbell's insights highlight centuries of confusion between literal and metaphorical interpretations of Western religious symbols that are, he argues, perennially relevant keys to spiritual understanding and mystical revelation.
all the best,