The basic and applied knowledge of cellular and molecular biology of human oogenesis, ovulation and early embryogenesis especially fundamentals, biomedical and clinical implications in relation to infant disorders for ensuring the formation of normal eggs or ova is essential. Keeping this in view, there is a great interest in the study of cellular and molecular biology of primordial follicles or oocytes and normal development, growth, differentiation and biochemistry of oogenesis i.e. oocyte growth, maturation, ovulation, fertilization of human ova in vivo and in vitro to develop better strategies for solving the problems of infertility and embryological disorders in women of various age groups. The exhaustive results on the study ovarian components have been subjected to diverse techniques of electron microscopy, histochemistry, cytogenetics, immunology, autoradiography, physiology, molecular biology, biochemistry in vivo and in vitro systems have been discussed in this book. The objective of this book is therefore to summarize and integrate the results obtained so far with these diverse techniques in order to provide a deeper insight into the basic subcellular and molecular aspects of human primordial follicles, oogenesis (oocyte growth and maturation), ovulation, fertilization and early embryogenesis with emphasis on developmental process involved in these aspects in humans at the cellular, subcellular and molecular levels in vivo and in vitro in women of various age groups for the better understanding of effects of aging, especially developmental abnormalities of the foetus involved in fertility and embryogenesis. The subject matter discussed in this book will provide rational interpretaion of alternations caused by prolonged action even in weak doses of different types of chemicals, drugs, stress, radiation as well as effects of cryopreservation and culturing of follicles or oocytes, fertilized eggs and early embryos in vitro in humans and other mammals. Various types of infant disorders in human as a result of aging of primordial oocytes and various clinical treatments are described in detail in relation to human oogenesis, ovulation and embryogenesis which is essential for basic biomedical scientists, clinicians etc.