Al Beruni was a renowned scholar from Persia who accompanied Mahmud during his invasion of India. In fact, he was the first Muslim scholar to do study on India and its culture and tradition. In addition to Arabic and Persian, he had good knowledge of Greek and Sanskrit.
He wrote several books on different subjects which included work on Geography, Mathematics, India, Literature, Astrology and cartography. Although he did not give too much details about wars and battles, he wrote extensively on traditions, customs and culture.
He wrote a famous book Tahqiq ma I- Hind. The book is related to Indian religion and Philosophy. He also wrote Kitab al-Qanun al-Masudi which is a fantastic book on Geography, Astronomy and Engineering.
Al Beruni also possessed scientific temperament. He calculated the height of the mountain using astrolabe.