Preface
On 1973 January 25 the Royal Society with the support of the Royal Astronomical Society celebrated the quincentenary of the birth of Nicolaus Copernicus by a symposium on planetary science followed by a reception. The work of Copernicus opened the way to sensible studies of the Sun and planets as a physical system and, down the long course of history, this has led directly to the emergence of almost the whole of modern physical science. As the symposium lectures (chapters 2-5 of this volume) abundantly demonstrate, however, at this present time there is a greater and more productive interest in the physics of the Solar System itself than there has been, it could well be claimed, since the work of Newton which, through that of Kepler, depended so essentially upon the work of Copernicus.