Shaykh Abul-Hasan Ali Nadwi was from the Indian Hasani descendents of the Prophet (may Allah bless him and grant him peace) and a luminary of a famous and renowned scholarly family. Even though he was from the UP district of Rai Bareilly, he spent his life in Lucknow. He was the Nazim (principal) and the chair of the All-India Muslim Personal Law Board. Along with being a great Islamic thinker, preacher and guide, he was a successful author and he had equal command of both oral and written Urdu and Arabic. He has written several books, the most famous of which is: What has the world lost because of the downfall of the Muslims? His pen exuded empathy for humanity and acted as a representative of Islamic thought. Through his speech and writing, he presented the authentic Islamic thought and methodology. Alongside his leadership of Nadwa and the Personal Law Board, he was responsible for and a patron of a number of religious and social organisations. His religious and social activism spans a period of more than half a century. Translation by Dr Mohiuddin Ahmad.