Certain products we associate with the manufactures of the household, so familiar and of such long standing that we do not think of them as requiring investigation or any special support of science. The older ones of us look back on cheese as an ancient home product; yet the old-fashioned hard strong kind has given place to many named varieties, some of them bearing little resemblance to the product of the kitchen and the buttery. We have analyzed the processes; discovered microorganisms that hinder or help; perfected devices and machines; devised tests of many kinds; studied the chemistry; developed markets for standardized commodities. Here is one of the old established farm industries that within a generation has passed from the housewife and the home-made hand press to highly perfected factory processes employing skilled service and handling milk by the many tons from whole communities of cows. This is an example of the great changes in agricultural practice. Cheese-making is now a piece of applied science; many students in the colleges are studying the subject; no one would think of undertaking it in the old way: for these reasons this book is written.

This book is intended as a guide in the interpretation of the processes of making and handling a series of important varieties of cheese. The kinds here considered are those made commercially in America, or so widely met in the trade that some knowledge of them is necessary. The relation of cheese to milk and to its production and composition has been presented in so far as required for this purpose. The principles and practices underlying all cheese-making have been brought together into a chapter on curd-making. A chapter on classification then brings together into synoptical form our knowledge of groups of varieties. These groups are then discussed separately. The problems of factory building, factory organization, buying and testing milk, and the proper marketing of cheese, are briefly discussed.

Such a discussion should be useful to the student, to the beginner in cheese-making, as a reference book on many varieties in the hands of makers who specialize in single varieties, and to the housekeeper or teacher of domestic science. The material has been brought together from the experience of the writers, supplemented by free use of the literature in several languages. Standard references to this literature are added in the text.

No introduction to the subject of cheese should fail to mention the work of J. H. Monrad, who has recently passed away. Mr. Monrad never collected his material into a single publication, but his contributions to chees-emaking information, scattered widely in trade literature over a period of thirty years, form an encyclopedia of the subject.

Bulletins of the Agricultural Experiment Stations and United States Department of Agriculture have been quoted extensively, with citation of the sources of the material. Personal assistance from Professor W. A. Stocking and other members of the Dairy Department of Cornell University, and C. F. Doane of the United States Department of Agriculture, is gladly acknowledged.

Students cannot learn out of books to make cheese. They may, however, be aided in understanding the problems from such study. To make cheese successfully they must have intimate personal touch with some person who knows cheese. Sympathetic relations with such a teacher day by day in the cheese-room are essential to success in making cheese which, at its best, is one of the most attractive of food-products.

The Authors.