Part I. The origins and features of basins and channels -- Lake basins and lakes -- Stream channels and streams -- Estuaries -- Part II. Water -- The nature of water -- Part III. Natural waters as environment -- Solar radiation and natural waters -- Thermal relations in fresh and estuarine waters -- Natural waters in motion -- Gases in lake, stream, and estuarine waters -- Dissolved solids in natural waters -- Part IV. Organisms in the environment -- Protists and plants in inland waters and estuaries -- The animal inhabitants of inland waters and estuaries -- Part V. Relationships of organisms and environment -- Populations in aquatic environments -- Aquatic communities.