Book excerpt: The endometrium goes through cyclical changes under the influence of hormones, and immune effectors in the endometrium change their populations cyclically as well. Dynamic changes in immune effectors determine endometrial cytokine and chemokine milieus and, consequently, the endometrial immune response. Endometrial immune responses have been shown to be important for trophoblast invasion and early pregnancy. Indeed, dysregulated endometrial inflammatory immune responses are associated with reproductive failures, such as recurrent pregnancy losses, repeated implantation failure, and gynecological diseases with oncogenic potential. Hence, the investigation of endometrial gene expression may predict infertility, gynecological and oncological conditions. This book presents the state of the art in endometrial gene expression as well as recent developmental findings relating to reproduction and reproductive disorders. It begins with a review of the genetic regulation of urogenital tract formation and molecular mechanism underlying the physiology of menstrual cycle before moving on to the current and emerging technological advances in molecular biology. Endometrial gene expressions of immune inflammatory conditions, viral infection, metabolic and nutritional conditions, and reproductive disorders are then presented in following chapters. Examples of the use and interpretation of gene expression in clinical scenarios including recurrent pregnancy losses, infertility and multiple implantation failures are presented with currently available endometrial gene analysis. Utilizing the latest evidence and clinical guidelines, Endometrial Gene Expression will be a cutting-edge resource for gynecologist, reproductive immunologist, reproductive endocrinologists, obstetrician, maternal fetal medicine specialist and other health care providers in the field of reproductive medicine.