The developing countries are in desperate need of development in order to met the basic essentials for life of its teeming millions. The developing process profoundly alters the delicate environmental fabric with concurrent beneficial and adverse impact on status of the environment. About Author : Prof. Dr. P R Trivedi Chairman, Indian Institute of Ecology and Environment, New Delhi. Contents : PrefaceConcepts of EcologyCommunity EcologyEcosystem EcologyMajor Ecosystems of the WorldGeographical EcologyMarine EcologyEvolutionary EcologyIndex