Dynamo theory then and now

A brief history of dynamo theory is presented, from its earliest beginnings, through the development of successful kinematic models (those in which only the electrodynamic equations are solved), up to the present time when fully magnetohydrodynamic simulations have successfully reproduced the main features of the Earth's magnetic field. A particular focus of this paper is the role of the solid inner core of the Earth on the dynamics of its fluid core. Some new results are presented concerning the age and topography of the inner core. (C) 1998 Elsevier Science Ltd. All rights reserved.