This monograph describes the physical principles of adhesion between particles and surfaces. These principles are applied to pharmaceutical processes involved in the manufacture of solid dosage forms such as powders, granules, tablets and dry powder inhalations. To help in the understanding of these systems, physical properties of solid surfaces, and an introduction to the theory of friction is given. Techniques for measuring particle adhesion and fracture mechanical properties of powders are introduced, as far as these are relevant to the processes discussed. The philosophy of the book deviates from that of standard pharmaceutical textbooks, in that it focuses primarily on physical principles involved in the manufacture of dosage forms rather than describing these processes purely by observation.