Colloid and Interface Science, Volume I: Plenary and Invited Lectures contains papers presented at the International Conference on Colloids and Surfaces, held in San Juan, Puerto Rico, 21-25 June 1976. It consists of the plenary and invited papers, and a general overview of these papers by A. M. Schwartz. These papers were given during the morning sessions. The volume is organized into 10 parts. Part I contains papers on surface forces. Parts II and III present studies on catalysis and aerosols, respectively. Part IV examines solid surfaces, focusing on newer techniques for exploring surface structure and surface reactions. The papers in Part V deal with water at interfaces, including a lecture on the behavior and structure of water at inorganic surfaces including metals, oxides, and silicates. Part VI covers the rheology of disperse systems, including papers on the effect of inertial forces on the motion of solids through liquids and theoretical studies on diffusive heat flux. Part VII takes up stability and instability in disperse systems, steric stabilization, and colloidal stability. Parts VIII and IX examine biological membranes and surface thermodynamics, respectively. Part X on liquid crystals includes discussion of the structures and properties of this state of matter.