Introduction. Physical Description of Single-Screw Extrusion. Fundamentals of Polymers. Theories of Single-Screw Extrusion. Screw Design, High Performance Screws, and Scale-Up. Gear Pump, Static Mixer, and Dynamic Mixer. Die Designs. Viscoelastic Effects in Melt Flow. Special Single-Screw Extruder with Channels on the Barrel. Physical Description of Twin-Screw Extruders. Appendices: Color Figures. Universal Constants, Unit Conversion Factors, and Prefixes.