This lecture explores the crystalline phase of polymers, focusing on the process of crystallization. Topics include the structure of semicrystalline polymers, the importance of intermolecular interactions, the role of polymer stereochemistry, and the effect of chemical structure on the melting temperature. The instructor discusses nucleation, growth, and the kinetics of bulk crystallization, as well as the Avrami equation. Various models and diagrams are used to illustrate the concepts.