Book Review of Advances in Nonlinear Dynamos, by Antonio Ferriz-Mas and Manuel Núñez, The Fluid Mechanics of Astrophysics and Geophysics, Vol. 9, Series Editors A.M. Soward and M. Ghil, Taylor and Francis, London, New York, 2003, IX + 384 pp., £80.00, hardback (ISBN 0-415-28788-X)