Amphiphilic molecules, or amphiphiles, not only are highly interesting from physicochemical view point but also fundamental to life and living bodies. Colloidal and interfacial phenomena of amphiphiles play a significant role in many aspect of our modern society. There has been a renewed interest in behavior of amphiphiles in solution in the last three decades. One of the main reasons for this renaissance is the increasing use of these amphiphiles in every industry sector, especially in applications to enhance crude-oil recovery. The purpose of this book is therefore, to elucidate different physicochemical properties of some simple amphiphiles including lithium dodecyl sulfate and also their mixture in aqueous and aqueous-organic mixed solvents. Besides presenting simple facts and concepts, the book also examine the different physicochemical properties of these amphiphilic substances using various existing theories of micellization. This book intended to provide an appreciation of pure and mixed amphiphiles to all those interested in chemical sciences and should be especially useful to the researchers of colloid and interface science.