Gevurat Anashim is a work of the Shach (Rabbi Shabbatai ben Meir HaKohen, know for the acronym of his commentary on the Yoreh De’ah section of the Shulchan Arukh, the “Siftei Kohen”) on Shulchan Arukh, Even HaEzer, section 154:7. The section discusses a case in which a woman wants her husband to issue her a get (writ of divorce) on the basis that he lacks “the strength of men” (“gevurat anashim”) to perform sexually. In his introduction, the Shach writes that he was unsatisfied with the treatment of the subject in the Shulchan Arukh and commentators and therefore felt compelled to write his own work.