Suspension polymerization is a heterogeneous process in which a water-insoluble liquid monomer containing an oil-soluble initiator is dispersed as droplets in a continuous aqueous phase and polymerizes within those droplets. Mechanical agitation establishes droplet size, while protective colloids or sparingly soluble inorganic stabilizers suppress coalescence ^[1]. Each droplet behaves approximately as a small bulk-polymerization reactor and is converted into a solid polymer bead, so particle size largely reflects the stabilized monomer-droplet distribution ^[2]. The continuous phase removes heat but does not normally contain the principal radical population. Suspension polymerization is therefore distinct from emulsion polymerization, where water-soluble initiation and micellar or particle nucleation produce particles much smaller than the original monomer droplets, and from dispersion polymerization, where a homogeneous starting solution generates precipitating particles. Pearl, bead, and inverse-suspension variants retain the defining architecture of polymerization in stabilized droplets dispersed in an immiscible continuous phase.