This book is intended to introduce the fundamental process that place in various components of the earth beginning with relationship between sun and earth, and then focusing on basics of physical environment i.e. atmospheric process, hydrological cycle, oceanography, lithosphere and soil environment. In the subsequent Chapters, biosphere and different kinds of ecosystems are introduced with emphasis on human impact on environment. Eventually current global environmental issues due to anthropogenic activity and their impacts are discussed. Each chapter begins with a case analysis or real world issue and then it is linked to the basic concept, deeper understanding of the scientific part followed by hints or linkages to the management. The book will be graduate students who wish to understand the environmental components in terms of fundamental process and scientific reasoning. The order of the chapters are sequenced as atmosphere, hydrosphere and lithosphere followed by interlinking biogeochemical processes that makes that ecosystem and human livelihood sustainable. Impact of human activities on the environmental components cyclic processes that governs earth is also discussed.