In the early 1500s, Martin Luther was challenged by Erasmus on the topic of 'free will.' Luther's response has become a classic in Christian theology. The difficult topics that Luther and Erasmus wrangled over are still difficult today; advances in science and philosophy have only made the question of 'free will' even more perplexing. Can Luther's reliance on 'sola scriptura' provide an answer that is relevant in the face of modern developments? Read for yourself, and decide. This edition, a well known translation by the Rev. Henry Cole (1823), contains an index of keywords, as well as an index of Bible references, to aid the serious researcher.