The present volume is an effort to meet the need for a simple and untechnical text to cover this secondary biology in its elementary phases. The book stands between the unorganized nature-study of the intermediate grades and the formal science of the more advanced courses. It is a difficult space to bridge, partly because the subjects are so diverse, and partly because some teachers do not yet understand the importance of imparting to beginners a general rather than a special view point. Still another difficulty is the lack of uniformity in the practice of different schools. It is not urged that it is desirable to have uniformity in all respects, but the lack of it makes it difficult to prepare a book that shall equally meet all needs. It is hoped, however, that the present book is fairly adaptable to a variety of conditions, and with this thought in mind the following suggestions are made as to its use: Being in three separate parts, the teacher may begin with plants, or with animals, or with human physiology. If a one-year course is desired, the topics that are printed in large type in Parts II and III may be used, and a choice from the chapters in Part I. For three half-year courses, all the parts may be covered in full. If the course in biology begins in the fall (with the school year), it may be well to study plant biology two days in the week and animal biology three days until midwinter; when outdoor material becomes scarce, human biology may be followed five days in the week; in spring, plants may be studied three days and animals two days. If the use of the book is begun at midyear, it will probably be better to follow the order in the book consecutively. If it is desired to take only a part of the plant biology, Chapters VI, XIV, XX, XXIII, XXIV may be omitted, and also perhaps parts of other chapters (as of X, XII, XIII) if the time is very short. The important point is to give the pupil a rational conception of what plants are and of their main activities; therefore, the parts that deal with the underlying life processes and the relation of the plant to its surroundings should not be omitted. If more work is wanted it is best to provide the extra work by means of the study of a greater abundance of specimens rather than by the addition of more texts; but the teacher must be careful not to introduce too much detail until the general subject has first been covered. The value of biology study lies in the work with the actual things themselves. It is not possible to provide specimens for every point in the work, nor is it always desirable to do so; for the beginning pupil may not be able to interest himself in the objects, and he may become immersed in details before he has arrived at any general view or reason of the subject. Great care must be exercised that the pupil is not swamped. Mere book work or memory stuffing is useless, and it may dwarf or divert the sympathies of active young minds.