This chapter describes the fundamental knowledge necessary for understanding colloidal organization phenomena. The main subjects are the following: (1) Substances are assemblies of their elementary particles; (2) properties of substances originate from the thermal movement of the elementary particles; (3) instability at interfaces; (4) various type of solutes in aqueous media; (5) most colloidal particles are charged negatively in water; (6) ion binding; (7) electrical double layers; (8) stability of colloidal dispersion and DLVO theory; (9) diffusion, rotational relaxation, light-scattering, viscosity and viscoelasticity; (10) electrokinetic phenomena; (11) kinetic analysis of colloidal organization; (12) close-up color pictures, optical microscopy, and reflection spectroscopy; (13) microgravity experiments; (14) why colloidal organization takes place; (15) from atoms to galaxies; and (16) synthetic and biological colloidal particles.