Paul's statement that 'letter kills but the spirit gives life' [2 Corinthians 3.6] has had an extraordinary impact on Christian thought through the ages. It has been read both as affirming the saving power of the new covenant in comparison to the old, and as a key to hidden, spiritual meanings in the text of scripture. It is, however, an ambiguous phrase, followed by a tangled story. This book explores the Pauline distinction both in its original context and in its aftermath in the early church, the Reformation and modern Biblical Studies. It then considers a postmodern reversal, where ideas of 'Spirit' are often seen as 'deadly' and the openness of the 'letter' or text as life-affirming, and draws conclusions for Spirit in the world.