An ideal reference for infertility specialists and reproductive endocrinologists alike, this comprehensive text discusses current natural and mild approaches to in vitro fertilization (IVF) and the development of in vitro maturation (IVM) as a clinical treatment. It is divided thematically into four sections. Part I presents the basic science of ovarian endocrinology and the mechanism of oocyte maturation, including follicular development and the importance of mitochondrial changes. The differences between natural cycle IVF and stimulated IVF are presented in part II, including the standard ovarian stimulation protocols and their outcomes and the etiology, prevention and management of ovarian hyperstimulation syndrome (OHSS). Minimal and mild stimulation for IVF is discussed in part III, including mild stimulation protocols for oncofertility patients and the new minimally invasive INVO procedure.