Preface -- The Importance of Understanding the Nature of Scientific Knowledge -- Part I: General Features of Knowledge -- The Traditional Account of Knowledge -- Belief -- Truth -- Justification -- Evidence -- Basing a Belief on the Evidence -- A Problem for the Traditional Account of Knowledge -- Part II: Knowledge of Scientific Claims -- Explanation and Understanding -- From Explanation to Knowledge -- Part III: Challenges to Scientific Knowledge -- Skepticism about the External World -- Skepticism about Induction -- Empirical Evidence of Irrationality -- Anti-Realism about Science -- Part IV: Social Dimensions of Scientific Knowledge -- Gaining Scientific Knowledge from Others -- Knowledge in a Scientific Community -- Looking Back and Looking Forward