This book is written to meet the need for a consist textbook of ecology. The book describes the basic features of the modern ecology and is addressed to college students without special biological knowledge. The book can be used in high schools, technical colleges and other place there ecology forms part of the education, but where time does not permit a major review of the many ecological topics. This ecology book does not deal with species ecology' or autecology, i, e, single species relation to their surrounding, although these factors may be of importance for the understanding of many ecological conditions