It has been over 25 years since my original textbook on Ideal Magnetohydrodynamics was published. The book, I believe, was well received by the fusion community but, unfortunately, the publisher has long since gone out of business, making it quite difficult to obtain copies. As a result I have often been asked by students and colleagues to write an updated version of the original book and this volume is the result of that effort. The second volume describing extended MHD will be published in the future.

In writing the book I have found some similarities with my original MHD book but many differences as well. One might hope and expect that a considerable amount of new ideas and discoveries will have been developed over the past 25 years. The overall result is that about a third of the book is closely related to my original textbook, about a third has similar subject titles but has been entirely rewritten, and the final third is completely new. The material is largely based on an evolving course on MHD that I have been teaching at MIT for nearly 25 years.