There are many people who deserve our thanks. Our mentors, Mitchell Golbus and Joe Leigh Simpson, were among the visionaries who saw the key role genetics would play in the specialty of obstetrics and gynecology, and sparked our enthusiasm to be reproductive geneticists. We thank our wives, Joan Hogge and Ana Malinow, for their support of our careers, and especially for putting up with the time we spent “working on the book.” We are indebted to Drs Svetlana and Alexander Yatsenko for sharing their special expertise in molecular cytogenomics and laboratory genetics, respectively, and for helping with many of the figures used in those chapters. The inspiration for many of the cases discussed in the book came from our genetic counseling colleagues Michele Clemens, Deanna Steele, Abigail Peffer, Luanne Fraer, Beth Kladny, Mary Dunkle, and Darcy Thull, as well as our clinical genetics colleagues Dr Marta Kolthoff and Dr Neil Saller. Special thanks go to Adele Leibowitz who organized and prepared our various manuscripts into a coherent whole, and to our editor at McGraw-Hill, Alyssa Fried, who guided us through the conception and birth of this project. Finally, we thank the many residents and fellows who have provided feedback on what they needed to learn to incorporate genetics into their practice.