This text was prepared by William Gross:
One of the greatest mitzvot is that of ritual purity. This large format book is a compilation of the ritual laws concerning purity, specifically dealing with the rules for Nidah and the Mikvah.
R. Elhanan ben Samuel Zanvil Ashkenazi (1713-1780) served as rabbi in Schottland, near Danzig. At the age of eighteen he became rabbi of Fordon, Prussia, and in 1752 first rabbi of Schottland. He wrote various Talmudic commentaries and "ḥilluḳim," or discussions, as well as commentaries to the four "Ṭurim," but, with the following exceptions, they have not been published: His published works, in addition to Sidrei Tohorah are Ḥiddud Halakot, novellæ on the Niddah; Shiyyure Ṭohorah, novellæ on the laws of ṭevilah, or immersion, in the Yoreh De'ah (all published by Judah Löb b. Elhanan, Berlin, 1783). The "Or ha-Yashar" of Aaron Simeon b. Jacob Abraham contains two responsa of R. Elhanan ben Samuel.