This is the second edition of a book that has already demonstrated its value through vast use. It has been expanded to 956 pages with approximately 40% of the authorship altered. This change as mentioned in the preface is to provide a variety of viewpoints; it certainly does just that. In addition, the editors were more than liberal in the variety of formats accepted for publication, which adds to the value of this volume. Each contributor presented as much or as little as he felt was necessary.