Professor Orson W. Israelsen of the Utah State Agricultural College in the United States authored Irrigation Principles and Practices. The first edition was published in the United States in 1932, and a Russian translation was published in the Soviet Union in 1936. The second edition was published in the United States in 1950 after revision and expansion by the author. Professor Israelsen's new edition differs considerably from the first edition: Chapters 15, 16, and 17 were removed; Chapters 18, 19, and 20 were condensed; and certain passages in several chapters were deleted. At the same time, new chapters were added, including those on the drainage of irrigated lands and on irrigation administration in the United States. New material was also incorporated into several chapters: data on irrigated areas up to 1948 were provided; information was added on pumping water, well installations, and the calculation of water-lifting costs in the United States; materials on field moisture capacity, wilting moisture content, and water movement in unsaturated soils were expanded; salinity indicators for irrigation water and salt-tolerance data for various crops were included; data from American research work were updated and enlarged; and a new bibliography containing 300 references on irrigation was compiled. It should be noted that the irrigated-area statistics up to 1948 presented by the author differ from those provided by other authors, particularly Horne and Peterson. For example, according to Israelsen, the irrigated land area of India and Pakistan amounted to 24 million hectares, whereas British sources estimated it at 28 million hectares. The irrigated area of the Soviet Union in 1948 is listed in the book as 3.2 million hectares, while the actual figure was approximately twice as large. The calculations for furrow irrigation were omitted from Chapter 6. Information on this principal irrigation method in the United States is presented rather briefly and in an empirical manner. For example, it states that furrow lengths range from 100 feet (30 m) or less in orchards to one-quarter mile (400 m) in field crops, but no distinction is made within such a wide range. No mention is made of the functional relationship between furrow length and such factors as soil properties, slope, and other conditions. When discussing the minimum and maximum soil moisture contents, Professor Israelsen maintains that the availability of soil water to plants depends solely on soil properties and does not involve the physiological characteristics of plants, apparently because minimum moisture content itself is determined only by soil properties. This conclusion is difficult to accept. Based on the results of a series of experimental studies, the author further states that soil cultivation does not affect water-holding capacity, a view that does not accord with our experience. In the new Russian translation, Chapter 18, dealing with irrigation administration in the United States, was omitted because it was considered of no practical value to Soviet readers. In addition, Chapters 15 and 16 were condensed, and several tables containing material irrelevant to Soviet irrigation practice were removed. Appendix A, which contained questions and answers prepared for American students, was also omitted from the Russian edition. The book contains a large number of charts, illustrations, and photographs. However, one shortcoming is the lack of explanation in certain cases, such as for the construction of the tensiometer. In Figure 75, the furrows are not parallel, thereby eliminating the possibility of mechanized soil cultivation with multi-share cultivators. In terms of content, the second edition by Professor Israelsen remains essentially a textbook intended for students, and the material cited is drawn primarily from American practice. The book provides a large amount of information on irrigation in the United States. Of particular interest to Soviet readers may be the methods of soil profiling, groundwater extraction, pump construction, subsurface storage of surface water and its use for irrigation, irrigation techniques, and machines used for lining and finishing canal surfaces. All numerical values in the book were converted into metric units during editing.