This book presents evolutionary ecology as a unified discipline rooted in Darwin's work, emphasizing the interplay between ecological processes and evolution by natural selection, both operating within Earth's physical systems. While it covers core topics such as population dynamics, species interactions, and ecological succession, it distinguishes itself through its focus on evolutionary game theory, life-history strategies, and foraging ecology. Complex ideas are accessible through natural-history examples and clear, intuitive graphics with minimal mathematics. The narrative extends into applied areas-including biodiversity, climate change, human evolution, and cancer biology-demonstrating how an eco-evolutionary perspective provides a coherent framework for understanding the natural world.