This essential textbook delves into the fundamental principles of ecology and the critical issue of pollution. Authored by Prof. Dr. Ihsan Fleih Al-Johary, it serves as a comprehensive guide for students of environmental science, exploring ecosystems, biodiversity, energy flow, and the various types of pollution—their sources, impacts, and potential remedies. It provides a solid foundation for understanding the complex interactions within our environment and the challenges we face in preserving it for future generations, making it an indispensable resource for anyone interested in the field.