This book presents various scientific and technical aspects of steroids. It provides an explanation of the basic science of steroids and is aimed at catering to the professionals engaged in health services. It should be kept in mind that medical science evolves at a rapid pace and a few important concepts, like the understanding of steroids and their therapeutic use, may readily transform with emergence of new concepts. Steroids can be either synthetic fat-soluble or naturally occurring organic compounds. They are present in fungi, plants and animals. They mediate a varied set of biological responses. Among these, cholesterol is the most common steroid in the body. It is an important part of cell membranes and also the starting point for the synthesis of other steroids. The aim of this book is to provide valuable information to the readers and enrich their knowledge about this interesting medical topic of steroids.