His expertise expanded to many fields including
Hadith,
Fiqh,
Usul al-Fiqh,
kalam (
theology),
logic,
grammar,
rhetoric, exact and
natural sciences. His knowledge was vast and incisive through which he was able to summarise many important and difficult topics succinctly. He authored of a number of influential works in the
Hanafi madhhab. His al-Tanqih (), along with his own commentary upon it entitled al-Tawdih (), is a work of
usul al-fiqh that merges between 'the way of the jurists' (i.e. the Hanafis) and between 'the way of the
scholastics', combining and reorganising the works of the Hanafi
Fakhr al-Islam al-Bazdawi and the
Maliki Ibn al-Hajib into a new synthesis. This work reflects a new development in the scholasticization of Hanafi jurisprudential theory. He authored a work (yet unpublished) known under the title Ta'dil al-'Ulum (), which became a milestone in the development of the
Maturidi kalam in
Khorasan and Ma Wara' al-Nahr (
Transoxania). His Ta'dil al-'Ulum was recommended by the sixteenth-century Ottoman scholar and judge
Ahmed Taşköprüzade (d. 1561) to anyone desirous of reaching the highest degree of excellence in
logic.
Astronomy Sadr's astronomical work represents an ongoing revision of
Ptolemaic astronomy. In that context, he undertook to correct the works of two of his predecessors, namely
Nasir al-Din al-Tusi and
Qutb al-Din al-Shirazi. The models of the last two were developed in their two respective works, the Tadhkira and the Tuhfa. Sadr took it upon himself to solve the problems they did not tackle, and to supply answers to the subtleties they did not address. Sadr's astronomical writings are found in the third volume of his three‐volume encyclopedia of the sciences, the ''Ta'dil al-'Ulum
(The Adjustment of the Sciences). The first two volumes dealt with logic and kalam. The third volume was called Kitab Ta'dil Hay'at al-Aflak'' (The Adjustment of the Configuration of the Celestial Spheres). This encyclopaedia starts with
logic, proceeds through
theology, and ends with
astronomy. It was written in
Bukhara, and was finished shortly before the death of its author. This work of Sadr is written in the traditional form of a commentary, where he gives his own text and then comments on the same. As is usual in such commentaries, the text is separated from the comments by the classical notation: a sentence preceded by the Arabic mim (short for matn) refers to the text, whereas the latter shin (for sharh) introduces the comment to that specific text. As a result, the work became voluminous, reaching some seventy densely written folios. == Death ==