The process of creating objects of a fixed cross-sectional profile is known as extrusion. During this process, a material is pushed through a die that has the desired cross-section. Extrusion is advantageous over other manufacturing processes because it has the ability to create very complex cross-sections. It may be continuous or semi-continuous. Continuous extrusion process can produce an indefinitely long object. Whereas semi-continuous extrusion produces many pieces. Extrusion can be done with hot as well as cold materials. Some of the commonly extruded materials are ceramics, polymers, modeling clay, metals and foodstuffs. The products made after extrusion are generally known as extrudates. The various advancements in extrusion are glanced at and their applications as well as ramifications are looked at in detail in this book. From theories to research to practical applications, case studies related to all contemporary topics of relevance to this field have been included herein. This book will serve as a valuable source of reference for graduate and post graduate students.