The subject of incestuous marriage has been one of the most controversial issues and debates in Iranian history. Not many historians have paid attention to this matter and it seems that even studying this topic is taboo, especially among Iranian scholars. On the other hand, the problem has gotten more complicated since the Islamic revolution, as some zealous islamists use this to humiliate the pre-Islamic history of Iran. Subsequently, Iranian nationalists and patriots have denied the existence of any incest in ancient Persia. In such a political environment, very few Iranian scholars have come up with valuable historical research, free of any prejudices. Yet their research is still scant compared to their Western colleagues. That is why Paul John Frandsen’s Incestuous and Close-KIN Marriage in Ancient Egypt and Persia should be taken seriously, as it evaluates many previous opinions about incest in ancient Iran with a critical approach, highlights their flaws, adopts a new method, and proposes new hypotheses. As the name of the book suggests, this work is about ancient Persia (Iran) and Egypt and explains that no direct link can be seen between incestuous marriage in these two ancient civilizations. This review concerns the part of the book dealing with Persia.