This book has been prepared primarily to serve students in horticulture, food chemistry, and horticultural products. Therefore the application of the fundamental sciences to the manufacturing and preserving processes concerned is given prominence equal to that of the strictly practical phases. The book is based upon lectures given by the author to students in fruit and vegetable products during the past twenty years and the subject matter is developed from the viewpoint of the instructor rather than from that of the manufacturer. Nevertheless, it is believed that commercial canners and others engaged in the fruit and vegetable products industries will find most of the information given upon their respective industries of direct value in the operation and control of their plants. In addition to serving as a reference book for the factory manager, superintendent, or chemist, the book will be of value to the foremen and other employees in the organization who desire to increase their technical knowledge of the industry. In conjunction with the "Laboratory Manual of Fruit and Vegetable Products" by Cruess and Christie, the present book may be used as a text for university and college courses in the subject. The list of references given at the end of each chapter may be used by the instructor in assigning outside reading or by chemists and others who may wish to consult original sources. Fruit and vegetable products have long been important articles of commerce and for many centuries have formed a large proportion of the diet of man. Many of these products were first prepared in the household on a small scale before their commercial production was undertaken, and others, since the beginning of their manufacture, have been prepared on a factory scale. Some may be termed "primary products," since the fruit and vegetables used are grown principally for the manufacture of the products concerned. The canning of fruits and vegetables, the pickling of cucumbers, and the manufacture of tomato catsup are primary industries. The manufacture of vinegar from waste fruits, of fixed oil from apricot kernels and raisin seeds, and of charcoal from fruit pits or hulls are by-product industries, since only fruit waste is used. Both primary products and by-products are important in relation to modern fruit and vegetable growing. In order that this book may not cover too wide a field, attention will be centered principally upon those industries more directly affecting the fruit and vegetable grower rather than the producers of field crops and of livestock. The intelligent application of scientific methods and principles in the fruit and vegetable products industries has been comparatively recent. Although notable advances have been made in the knowledge of the fundamental scientific principles underlying processes used in these industries, there remains to be done a vast amount of research before the manufacturing processes are placed upon the same high plane of efficiency and applied science as, for example, obtains in the manufacture of beet sugar. The opportunities for investigation by chemists, physicists, bacteriologists, and engineers in the fruit and vegetable products field are almost unlimited.