Front Matter -- Preface -- Acknowledgment of Reviewers -- Contents -- 1 Background and Goals -- 2 Predictability Science: Definitions -- 3 Challenges in Predictability Science and Limits-to-Prediction for Hydrologic Systems -- 4 Conclusions -- References -- Appendix A Workshop Agenda and List of Participants -- Appendix B Selected Papers Presented at Workshop on Predictability and Limits-to-Prediction In Hydrologic Systems -- Appendix C National Research Council Board Membership and Staff -- Appendix D Biographical Sketches of Members of Committee on Hydrologic Science.