This document discusses theories of dispersion and methods for preparing emulsions and suspensions. It covers four main theories of emulsion dispersion: viscousity theory, film or adsorption theory, wedge theory, and interfacial tension theory. It also describes common emulsion preparation methods like the dry gum method and wet gum method. For suspensions, it defines suspensions and covers methods like dispersion, precipitation including organic solvent precipitation and pH-induced precipitation, and double decomposition. It discusses factors that influence emulsion and suspension stability and methods to improve stability.