Geomagnetism in perspective / M. Kono -- The present field / G. Hulot, T.J. Sabaka, N. Olsen -- Magnetospheric contributions to the terrestrial magnetic field / W. Baumjohann and R. Nakamura -- Observation and measurement techniques / G.M. Turner, J.L. Rasson, C.V. Reeves, Geomagnetic secular variation and its applications to the core / A. Jackson and C.C. Finlay -- Crustal magnetism / M.E. Purucker, K.A. Whaler -- Geomagnetic induction studies / S. Constable -- Magnetizations in rocks and minerals / D.J. Dunlop and Ö. Özdemir -- Centennial- to millennial-scale geomagnetic field variations / C. Constable -- Geomagnetic excursions / C. Laj, J.E.T. Channell -- Time-averaged field and paleosecular variation / C.L. Johnson, P. McFadden -- Source of oceanic magnetic anomalies and the geomagnetic polarity timescale / J.S. Gee, D.V. Ken -- Paleointensities / L. Tauxe, T. Yamazaki -- True polar wander : linking deep and shallow geodynamics to hydro- and bio-spheric hypotheses / T.D. Raub, J.L. Kirschvink, D.A.D. Evans