This painstakingly researched book written by Dr Farokh Erach Udwadia titled “Rivalry Between the Parthian and Sasanian Persian Empires and Rome: The Rise and Fall of the Sasanian Empire deals with the last two great Persian Dynasties, the Parthian and Sasanian Empire”, which rose to power between 3rd BC and 7th CE. It describes the rivalry between the Persian Empire and the Roman Empire which had by then become the immediate neighbour of the Persians.