In this study, the sources of the Delhi Turkish Sultanate written in Indic languages between the 12th and 14th centuries are introduced. Their essential features, historical value, and some problems are summarized in this respect. The Delhi Turkish Sultanate has a vibrant diversity of primary sources. Although most of these sources were written in Persian by Muslim names, there are also significant works written in the prevalent languages (Sanskrit, Prakrit, etc.) in the Indian subcontinent by the non-Muslim subjects of the Sultanate. Accordingly, the scope of the study has been determined as the works written in the Indic languages (Sanskrit, Prakrit, etc.) between the 12th and 14th centuries. Introducing the publications and translations of these sources, which are almost unknown to our academic writings and are not used in history studies except for a few minor references, may gain a different perspective and depth to the studies of Delhi Sultanate and medieval India carried out in Turkey. Therein, it has been determined that the works of Ṭhakkura Pherū (b. ca. 1270 A.D.), a Jain assayer who served in the Sultanate's treasury during the Khaljī dynasty, contain precious information. Pherū is a versatile scholar who has left seven works on miscellaneous subjects. His works, written in the Apabhraṃśa dialect, were unearthed in 1946 and were gradually made obtainable in publications and English translations. Some of his identified works are: Jyotiṣasāra is about astronomy and astrology, Dhūtātpatti is about metallurgy and perfumery, Dravyaparikṣā is about numismatics and exchange of coins, Ganitasāra is about arithmetic, Vastusāra is about architecture and iconography, and Rayaṇaparikkhā is about gemology. Besides these, there are other monographs assessed in the Jain religious literature. It has been determined that Dravyaparikṣā and Rayaṇaparikkhā, which are among the aforementioned works written between 1291 and 1323 A.D., contain tables, lists, and explanations showing the crop/land or coin/alloy ratios, which provide precious data on the economic circumstances of India in the middle ages. The data in these tables, created according to the Indian medieval metric and weight systems, were translated into modern measurement standards through English translations and evaluations and brought to Turkish literature. Moreover, it has been revealed that the interlinear information provided by Pherū holds essential glimpses into the essence of Muslim-non-Muslim relations in the Sultanate. At the end of the study, it is pointed out that detailed expert evaluations of Pherū's works will make significant contributions not only to the studies of the Delhi Turkish Sultanate but also to the medieval science history literature.