Flow-induced Crystallization (FIC) is an important area in polymer processing and has since a long time been researched intensively. Here, the FIC study extends into the high flow rate range, comparable to that encountered in real processing, and considers two main flow types: shear and elongational. The second topic is to investigate the effects of several molecular parameters on the crystallization behaviour. Polybutene-1 (PB-1) was chosen as the research material because of its relatively slow crystallization kinetics, allowing observations to be made without too much difficulty. It is the aim of this book to improve the knowledge concerning FIC and suggest an empirical model that is able to represent the material behaviour well.