Crystallization plays a critical role in pharmaceutical development not only because of its economical importance in large scale purification and great potential in optical resolution, but also because it is the only means of producing the desired crystalline forms of active pharmaceutical ingredients. Polymorph control is an essential process development activity, as polymorphism can alter physical properties that affect drug performance and stability. Although crystallization is one of the oldest technologies, establishing successful and robust conditions for producing specific polymorphs has been done by trial and error due to a lack of fundamental understanding of the thermodynamics and kinetics that govern the process. Knowledge of factors controlling the formation of crystals is thus demanded at both the bulk and molecular level. This paper attempts to link structural features of crystals, molecular conformations and intermolecular interactions, with nucleation where the atoms arrange in a defined and periodic manner that defines a crystal structure. Particular emphasis will be directed to observations of homochiral compounds that form crystals whose structures mimic the structures of their racemic forms. These pseudoracemic structures appear to have a significant impact on nucleation.