The androgen receptor (AR) mediates a wide range of physiological actions of androgens in cells and tissues. Contributions to this volume cover distinct topics of AR signalling, extending from the structural aspects of AR to its role in androgen-associated diseases and potential clinical applications. Some key issues covered include an overview of structural aspects of AR genes and proteins in mammalian and non-mammalian vertebrate species and a description of the identified AR splice variants in pathological and non-pathological conditions. The structural and functional analysis of coding and untranslated regions of AR are discussed in the context of diseases such as androgen insensitivity syndrome, spinal and bulbar muscular atrophy, polycystic ovarian syndrome and breast, ovary and prostate cancers. The role of AR regulated genes implicated in prostate cancer progression is also explored. This book is a comprehensive conceptual review of the recent findings on AR genes and protein structure, molecular variants, ligands, target genes and signalling mechanisms. Graduate students, scientists and professionals can use it as both a study text and a reference for research purposes.