There have been people who insisted on leaving their imprints on life, and this is why history has immortalized their mention. They formed the civilization of their Ummah (nation); their renaissance became a source of goodness and light for the entire world, and they were the lanterns which lit the way for the West during their age of darkness.

　　Al-Hasan and his beneficial knowledge

　　He is Al-Hasan ibn Al-Haytham (often known as Alhazen, the Latinized version of his first name "al-Hasan") . He was born in Basra, Iraq, and studied medicine, astronomy, geometry, mathematics and physics.

　　Among his important books of optics, a mention may be made of Al-Manaathir (Latinized Opticae = Book of Optics), in which he studied the theory of refraction and reflection of light in transparent media like water and air. It continued to be the main reference for that science in Europe until the end of the seventeenth century CE. In this book, he laid the foundation of the discovery of the physical principle on which both the microscope and telescope are based.

　　The National Library of Paris contains many of his books and manuscripts in which he deals with some branches of geometry. Others are at the Bodleian library at Oxford. He compiled 43 books on philosophy and physics, 25 books on mathematics, 21 books on geometry, and 20 books on astronomy and arithmetic. It is mentioned that the total number of his books handed down to us is approximately 200, all of which he prefaced with the following wonderful words: "As long as I live, I am going to devote my effort, mind and energy to knowledge for three reasons:

　　1- To benefit the one who seeks knowledge during my lifetime and after my death.

　　2- To be a treasure for me in my grave and on the Day of my reckoning.

　　3- To make superior the power of Muslims."

　　The determination of Al-Bukhari:

　　He said, "Once, I was in the house of Is-haaq ibn Raahawayh when one of our companions suggested the compilation of an abridged book of the Sunnah (acts, deeds and sayings) of the Messenger of Allah . I was impressed by the suggestion, and started to compile this book.” [Siyar A‘laam An-Nubalaa’]

　　Serving the Sunnah of the Prophet was the mission for which Al-Bukhari pledged his life since he was ten years old. Allah The Almighty endowed him with his vision in this blessed gathering (in the house of Ibn Raahawayh), which he realized by traversing the lands from his native Bukhara on long journeys, collecting the Hadeeths (narrations) of the Prophet, sallallaahu ‘alayhi wa salam, passing by Balkh, Marw and Naysaaboor, before he entered Iraq and travelled between its different cities. Thereafter, he went to Makkah and then Madeenah and completed his journey by visiting Egypt and Ash-Shaam.

　　Al-Bukhari said, "I composed the Saheeh (Book of Authentic Hadeeths) in sixteen years." [Siyar A‘laam An-Nubalaa’] He further said, "I have produced this book out of approximately six hundred thousand Hadeeths." [Sifat As-Safwah: Ibn Al-Jawzi]

　　He was a miracle in the power of memorization and intelligence. He said about himself, "I have memorized about one hundred thousand authentic Hadeeths, and two hundred thousand unauthentic Hadeeths." [Fat-h Al-Baari: Ibn Hajar]

　　When will you leave your trace?

　　O you, upon whom Allah The Almighty has bestowed Islam, and sufficient it is for a favor! O you, whose forefathers lit up the darkness of the world and established an astonishing civilization! Are you not alarmed by the present state of your Ummah (nation)? Are you not discomfited by the fact that the world exists for others, rather than you, with which they play, and make weapons that they direct towards the chests of your Ummah? Are you not worthier of precedence in the task of building?

　　Wake up and release yourself from the chains of inertia. Recognize your identity and look at the golden past of your Ummah, to draw a torch to light up the way for you. Hasten to work, and make your mark on life which is but a limited number of breaths, and you do not know at which point it would end. At that time, you will have nothing to leave in this world except your imprint upon it. If there is none, then, history would irretrievably fold your page. However, if you blaze a trail, people would stand by it and say: "He has passed away, and this is his legacy."