Complex fluids include polymers, colloids, emulsions, forms, gels, liquid crystals, surfacants, and other materials that form flowable microstructures. These substances are important in industries producing products such as plastic packaging, paint, ketchup, and toothpaste, and are of vital use to the petroleum, microelectronics, and pharmaceutical industries. This textbook provides both an introduction to these fascinating and important substances and an up-to-date synopsis of the latest advances in understanding the relationship between their structure and flow properties.