Steroids refer to biologically active organic compounds which generally have seventeen carbon atoms that are bonded in four fused rings. They are found in animals, plants and fungi. Steroids are components of cell membranes and also function as signaling molecules. On the basis of function, they can be classified into various types, such as neurosteroids, corticosteroids and sex steroids. Neurosteroids are steroids which interact with cell surface receptors and ligand-gated ion channels to alter neuronal excitability. Corticosteroids are a group of steroids which are produced by the adrenal cortex and are involved in a range of physiological processes such as carbohydrate metabolism, regulation of inflammation, protein catabolism, immune response and stress response. This book includes some of the vital pieces of work being conducted across the world, on various topics related to steroids and their relevance in brain functions. From theories to research to practical applications, case studies related to all contemporary topics of relevance to this area of study have been included herein. This book is a resource guide for experts as well as students.