FrontMatter -- Preface -- Acknowledgments -- Contents -- Executive Summary -- Summary -- 1 Introduction -- 2 Lessons from Past Warm Worlds -- 3 Climate Transitions, Tipping Points, and the Point of No Return -- 4 Deciphering Past Climates-Reconciling Models and Observations -- 5 Implementing a Deep-Time Climate Research Agenda -- 6 Conclusions and Recommendations -- References -- Appendixes -- Appendix A: Committee Biographical Sketches -- Appendix B: Workshop Agenda and Participants -- Appendix C: Presentations to Committee -- Appendix D: Acronyms and Abbreviations.