1. The MESSENGER mission: science and implementation overview Sean C. Solomon and Brian J. Anderson; 2. The chemical composition of Mercury Larry R. Nittler, Nancy L. Chabot, Timothy L. Grove and Patrick N. Peplowski; 3. Mercury's crust and lithosphere: structure and mechanics Roger J. Phillips, Paul K. Byrne, Peter B. James, Erwan Mazarico, Gregory A. Neumann and Mark E. Perry; 4. Mercury's internal structure Jean-Luc Margot, Steven A. Hauck, II, Erwan Mazarico, Sebastiano Padovan and Stanton J. Peale; 5. Mercury's internal magnetic field Catherine L. Johnson, Brian J. Anderson, Haje Korth, Roger J. Phillips and Lydia C. Philpott; 6. The geologic history of Mercury Brett W. Denevi, Carolyn M. Ernst, Louise M. Prockter and Mark S. Robinson; 7. The geochemical and mineralogical diversity of Mercury Timothy J. McCoy, Patrick N. Peplowski, Francis M. McCubbin and Shoshana Z. Weider; 8. Spectral reflectance constraints on the composition and evolution of Mercury's surface Scott L. Murchie, Rachel L. Klima, Noam R. Izenberg, Deborah L. Domingue, David T. Blewett and Jörn Helbert; 9. Impact cratering of Mercury Clark R. Chapman, David M. H. Baker, Olivier S. Barnouin, Caleb I. Fassett, Simone Marchi, William J. Merline, Lillian R. Ostrach, Louise M. Prockter and Robert G. Strom; 10. The tectonic character of Mercury Paul K. Byrne, Christian Klimczak and A. M. Celâl Sengör; 11. The volcanic character of Mercury Paul K. Byrne, Jennifer L. Whitten, Christian Klimczak, Francis M. McCubbin and Lillian R. Ostrach; 12. Mercury's hollows David T. Blewett, Carolyn M. Ernst, Scott L. Murchie and Faith Vilas; 13. Mercury's polar deposits Nancy L. Chabot, David J. Lawrence, Gregory A. Neumann, William C. Feldman and David A. Paige; 14. Observations of Mercury's exosphere: composition and structure William E. McClintock, Timothy A. Cassidy, Aimee W. Merkel, Rosemary M. Killen, Matthew H. Burger and Ronald J. Vervack, Jr; 15. Understanding Mercury's exosphere: models derived from MESSENGER observations Rosemary M. Killen, Matthew H. Burger, Ronald J. Vervack, Jr, and Timothy A. Cassidy; 16. Structure and configuration of Mercury's magnetosphere Haje Korth, Brian J. Anderson, Catherine L. Johnson, James A. Slavin, Jim M. Raines and Thomas H. Zurbuchen; 17. Mercury's dynamic magnetosphere James A. Slavin, Daniel N. Baker, Daniel J. Gershman, George C. Ho, Suzanne M. Imber, Stamatios M. Krimigis and Torbjörn Sundberg; 18. The elusive origin of Mercury Denton S. Ebel and Sarah T. Stewart; 19. Mercury's global evolution Steven A. Hauck, II, Matthias Grott, Paul K. Byrne, Brett W. Denevi, Sabine Stanley and Timothy J. McCoy; 20. Future missions: Mercury after MESSENGER Ralph L. McNutt, Jr, Johannes Benkhoff, Masaki Fujimoto and Brian J. Anderson.