Many people learn the rudiments of the nitrogen cycle while at school, but the details of the various processes in the cycle are still not widely understood. Some of them are of great current interest, such as the use of nitrogen fixing crops to feed an increasing world population and the problems of pollution of groundwaters by nitrates. Denitrification (forming nitrogen gas) as a way of getting rid of waste from human and intensively farmed animals. This book describes the general processes of the nitrogen cycle, then gives examples of how the cycle is modified under particular ecological and geographical conditions. These examples are drawn from all the major areas of the world, and the impact of man via agriculture, forestry and fuel combustion is discussed. Numerous references are included. The book provides a background for all those whose specialist interests interact with nitrogen cycling, whether they are involved in research or have responsibility for managing the environment.