The mechanism for sorption of organic pollutants and pesticides by soil has long been a subject of profound interest because of its direct impacts on the mobility and activity of the compounds in soil. Although a large volume of laboratory and field data on many aspects of soil behavior had been gathered between the 1950s and 1970s, during which period the use of organic pesticides was increased, no general agreement was reached regarding the sorptive mechanism involved. Since the 1970s, the outgrowth of public concern over environmental contamination further stimulated research in this subject. The development of this field of research has now reached a point that the diverse characteristics of soil sorption can be placed in a much better perspective. This enables researchers to reexamine old and new data for consistency and for assessing the activity of organic pollutants and pesticides in soil.