This textbook is intended for use in the third and fourth grades, is divided into approximately 150 planned lessons for each year's work. These lessons are grouped into chapters, each composed of a series of related units that center about a common theme, providing work for a period equivalent in general to a school month. The material on which conversation and written exercises are based has been selected with reference to its interest to children and its vital relation to their experiences. The lessons are so arranged that oral discussion precedes and prepares for written expression. [For book two, see ED623130. For book three, see ED623131.]