The life of Imam Hasan (as) was both eventful and full of lessons, and yet the significance of his role seems to have been ignored, forgotten, or eclipsed by the extent of focus on Imam Husayn (as). A common misconception is that he was just a peace-maker, yet nothing could be further from the truth. For Imam Hasan (as) was overwhelmingly and popularly appointed as Caliph due to his charisma, knowledge and eminent piety. Then he led the Islamic Caliphate for six months with authority and control, and he prepared his army, leading it to war against Muawiya and exhorting it to be brave and unflinching. Moreover, the author demonstrates, with exacting scholarship using authentic sources and the motherbooks of history, how there would have been no Karbala without the groundwork laid by Imam Hasan (as). The book also has great value as a manual of instruction on how one should obey the Imam of one’s time, in war and in peace .Thus making it an excellent way of preparing for the emergence of the Twelfth Imam (ajtf).