The Foundations of Rheology discusses the main theoretical concepts of rheology as well as its practical applications in medicine, engineering, pharmacology, process technology, marine settings, cosmetics, and more. The book starts with coverage of the fundamental aspects of continuum mechanics that define stresses and related deformations, describing key principles, such as equations of conservation and applications of continuum mechanics in rheology. Discussion of the commonly understood principles of flow follows, such as those in Newtonian liquids and Hookean solids, as well as more complex phenomena of plasticity and linear viscosity. Non-linear effects in rheology are covered next, which includes fundamental treatment of non-Newtonian viscosity, elasticity of liquids, nonlinear viscoelasticity, and structural and temporary effects. Topics that are essential for commercial applications of many products such as thixotropy, other principles of structure formation, phase transitions, and system heterogeneities are also discussed. Subsequent chapters concentrate on applications of rheology to polymeric and dispersed systems, including discussion of the effects of molecular weight, concentration, temperature, elasticity, as well as instabilities, viscoelasticity, uniaxial extension, stress, rheokinetics, and structural transitions. The final chapter is devoted to the measurements of rheological properties with different types of viscometers, rheometers, plastometers, and penetrometers, including all available and most modern methods of measurement, their practical applications, and interpretations of results. Each chapter contains questions and answers to help readers check their mastery of the subject, and further elaborate on discussed topics.