It was a compliment to me to be asked to prepare the fourth edition of Westcott's Plant Disease Handbook, and the decision to accept the responsi bility for the fourth edition and now the fifth edition was not taken lightly. The task has been a formidable one. I have always had a great respect professionally for Dr. Cynthia Westcott. That respect has grown considerably with the completion of the two editions. I now fully realize the tremendous amount of effort expended by Dr. Westcott in developing the Handbook. A book such as this is never finished, since one is never sure that everything has been included that should be. I would quote and endorse the words of Dr. Westcott in her preface to the first edition: "It is easy enough to start a book on plant disease. It is impossible to finish it. " This revision of the Handbook retains the same general format contained in the previous editions. The chemicals and pesticides regulations have been updated; a few taxonomic changes have been made in the bacteria, fungi, and mistletoes; the changing picture in diseases caused by viruses and/or viruslike agents has been described. A few new host plants have been added, and many recently reported diseases as well as previously known diseases listed now on new hosts have been included. In addition, photographs have been replaced where possible, and the color photograph section has been retained.

The properties and modes of action of both the vitamins and the hormones, and their interrelationships to each other as metabolic controlling agents, are easily accessible in this handbook. The book was written to alleviate the continued frustration experienced by many people, including myself, when attempting to obtain unitary, basic information on vitamins and hormones. Although many of the data are separately available, they are so scattered in many compendia, original research papers, and reviews that a small research project on each vitamin and hormone is required before most of the data can be placed in proper context and profitably used. This feeling of dissatisfaction was brought to a head when I recently presented graduate courses in Endocrinology and on Vitamins and Hormones, thus providing the stimulus for this book. Much of the material, and the general format of this volume were generated from lecture notes for the course on Vitamins and Hormones. It is hoped that this book will be of use to researchers and students in the various fields of life sciences, as well as to physicians, pharmacologists, nurses, and dietitians. Moreover, this book has sufficient content of semitechnical language to make it useful to the educated layman who might need ready information to guide him through the vitamin fads of the day, including rational meal and cooking selections, and to aid in understanding the hormone-related articles in various newspapers and magazines.