This book brings together key findings, insights, and theories at the intersection of two disciplines – city science and complex systems. It features a curated collection of chapters contributed by emerging scholars conducting cutting-edge research in complexity science, interdisciplinary physics, and quantitative geography. The compendium is tailored to a thematically diverse audience, spanning quantitative fields such as statistical and mathematical physics, as well as socially-focused domains such as geography and urban planning. By integrating novel methods and insights from physics, economics, and geography, this book aims at an interdisciplinary spectrum of graduate students and academic researchers studying cities as complex systems.