The book "The Age of Al -Ma'mun" by its writer, Ahmed Farid Rifai, presents a presentation of the era of the Caliph Al -Ma'mun, as his era is considered one of the most advanced ages in the history of Islamic civilization. This progress includes various areas of life starting from military, scientific, cultural, literary, political, and ending social life. Al -Mamoun was able to overthrow his faithful brother and remove him from the ruling, in the conflict that was circulating to assume power, after their father, Harun al -Rashid, joined the supreme companion, and Al -Ma'mun was able to unite the ranks of the Islamic nation and subject them to his rule, and to eliminate all the cells of the sleeping rebellion, where it was Al -Ma'mun is known to be a lover of science and scholars, and there is a good mind, and it has deepened a lot in the sciences of the Noble Qur'an and philosophy, and he studied jurisprudence of doctrines, and Al -Maamoun was keen to provide a hand and assistance to each scientist, as he was interested in establishing hospitals and building schools and libraries, and all this The momentum and more, the historian Ahmed Farid Al -Rifai pushed to date the era of Al -Ma'mun, and to write about that historical period in his rule, as this book is a wonderful source of history sources, especially in light of the lack of sources available in this regard.