The Metaphysical Disputations provide an excellent philosophical introduction to the medieval Aristotelian discussion of efficient causality. The work constitutes a synthesis of monumental proportions: problematic issues are lucidly delineated and the various arguments are laid out in depth. Disputations 17, 18, and 19 deal explicitly with such issues as the nature of causality, the types of efficient causes, the prerequisites for causal action, causal contingency, human free choice, and chance.