Solar and Stellar Magnetic Activity Carolus J.Schrijver and CornelisZwaan Cambridge U. Press, New York, 2000. $80.00 (384 pp.). ISBN 0-521-58286-5

The study of solar and stellar activity is currently one of the most vibrant and interesting fields of astronomy. Solar physics is being revolutionized by many surprising discoveries from the SOHO (Solar and Heliospheric Observatory) space satellite, launched jointly by the European Space Agency and NASA, and from NASA’s Transition Region and Coronal Explorer (TRACE) mission. The observations from these missions are being eagerly examined, interpreted, and modeled by a new generation of lively young solar researchers, especially in Europe, but also in the US.

Stellar observations are becoming not only more numerous but also increasingly sophisticated, leading to the discovery of many solarlike phenomena (such as spots, flares, prominences, activity cycles, and global oscillations) on other stars. The detailed properties of these processes are being investigated in parameter regimes that are quite different from those on the Sun.

It is, however, astonishing that many fundamental properties of the Sun are not yet understood. These include the generation of magnetic fields by dynamos; the heating of the outer atmosphere (the corona); the acceleration of the solar wind (the particle outflow from the Sun); the power source of solar flares; and the trigger mechanism of great solar eruptions—coronal mass ejections. Study of each of these basic phenomena is crucial to an understanding not only of how they occur on other stars but also how our dynamic universe works in all its richness and diversity.

The key factor at the root of all these processes is the magnetic field and its subtle nonlinear interaction with the matter of the universe, most of which is in the plasma state.

In Solar and Stellar Magnetic Activity, Carolus J. Schrijver and his former thesis supervisor, Cornelis Zwaan, have produced a splendid book that reviews our current understanding of many key topics in solar and stellar activity. Tragically, Zwaan died soon after the manuscript was finished. He had been one of the leading figures in forging the so-called solar-stellar connection and understanding how solar phenomena occur on other stars. Schrijver is one of the leading solar-stellar physicists in the US.

The strength of the book lies in the clear overview it provides of activity both on the Sun and on other stars, from an observer’s viewpoint. It describes the physical processes at work without going into the mathematical details. Its particular forte is in its detailed description of the complex behavior of magnetic fields in the solar surface; that behavior drives a host of dynamic phenomena in the overlying corona. The book also reviews authoritatively the various components of stellar activity, such as starspots, activity cycles, and the evolutionary stages of stellar activity.

The area to be covered by any overview of this subject is enormous; inevitably, a few topics cannot be fully treated. For in-depth accounts of stellar magnetic field theory, the reader is advised to complement the Schrijver-Zwaan book with Leon Mestel’s Stellar Magnetism (Oxford U. Press, 1999), Eugene N. Parker’s Cosmical Magnetic Fields (Oxford U. Press, 1979), and Lectures on Solar and Planetary Dynamos, edited by M. R. E. Proctor and A. D. Gilbert (Cambridge U. Press, 1994).

Solar and Stellar Magnetic Activity is highly recommended for solar-stellar graduate students, for solar physicists wanting to learn more about other stars, and for stellar astronomers who are unfamiliar with recent developments relating to our Sun.