This document discusses different types of superchargers used to boost engine power. It describes how superchargers work by compressing air delivered to the engine, allowing for more fuel and a more powerful combustion. The document categorizes superchargers based on their compression methods and discusses common types like roots, twin-screw, and centrifugal superchargers in detail. It also covers why superchargers are used, how they provide advantages over turbochargers, and concludes that superchargers are still a cost-effective way to significantly increase an engine's horsepower.