"A valuable summary of the state of knowledge in regard to visibility under atmospheric conditions. … The book must be considered a most valuable addition to the literature on visibility, for which meteorologists are indebted to the author." (Bulletin of the American Meteorological Society) "To those already familiar with Dr. Middleton's writings, it will not be necessary to add that the book is written in a very clear, concise style, with however the few personal touches which distinguish a living text from a dry one." (World Meteorological Organization Bulletin)