This book covers the physical side of colloidal science from the individual forces acting between particles smaller than a micrometer that are suspended in a liquid, through the resulting equilibrium and dynamic properties. A variety of internal forces both attractive and repulsive act in conjunction with Brownian motion and the balance between them all decides the phase behaviour. On top of this various external fields, such as gravity or electromagnetic fields, diffusion and non-Newtonian rheology produce complex effects, each of which is of important scientific and technological interest. The authors aim to impart a sound, quantitative understanding based on fundamental theory and experiments with well-characterised model systems. This broad grasp of the fundamentals lends insight and helps to develop the intuitive sense needed to isolate essential features of the technological problems and design critical experiments. The main prerequisites for understanding the book are basic fluid mechanics, statistical mechanics and electromagnetism, though self contained reviews of each subject are provided at appropriate points. Some facility with differential equations is also necessary. Exercises are included at the end of each chapter, making the work suitable as a textbook for graduate courses in chemical engineering or applied mathematics. It will also be useful as a reference for individuals in academia or industry undertaking research in colloid science.