Colloids are ubiquitous in nature and essential for numerous technological innovations. The intricate surface properties of these systems drive vital research across diverse disciplines, including materials science, nano-chemistry, environmental processes, bioengineering, and medicine. This book provides a broad overview of the foundations of colloid and interfacial science. It details cutting-edge laser techniques for characterizing bulk and surface properties of colloids. Featuring groundbreaking developments in nonlinear optical spectroscopy and recent advances in interfacial chemistry, this book serves as an important resource for researchers, engineers, and budding scientists aiming to extend the frontiers of colloid science and technology.