What are elastomers and why are they significant in the world of engineering? Elastomers have very specific physical properties. They have the ability to resist high levels of deformation and spring back to their original shapes. This makes them excellent sealing materials. Essentially creating barriers between us and some of the most extreme and dangerous of engineering applications; aggressive chemicals, high-pressures and extreme temperatures (high and low). This tutorial provides an introduction to elastomers as an engineering material. It teaches the basic chemistry of what gives them their unique properties, the development of elastomers in industry and a brief overview of where different classifications of elastomers are used.