Rabbi Elazar ben Moshe Azikri (Hebrew: אלעזר בן משה אזכרי‎‎‎) (1533–1600) was a Jewish kabbalist, poet and writer, born in Safed to a Sephardic family who had settled in the Land of Israel after the expulsion from Spain. Rabbi Elazar studied Torah under Rabbi Yosef Sagis and Rabbi Jacob Berab, and is counted with the greatest Rabbis and intellectuals of his time: Shlomo Halevi Alkabetz, Yosef Karo, Moshe Cordovero, Isaac Luria, Israel Najara, etc. In 1588 Rabbi Elazar founded the "Sukat Shalom" movement who acted to arouse in Jews the devotion to religion. Rabbi Elazar died in 1600 and was buried in Safed. Rabbi Elazar's Book, the Sefer Haredim (ספר חרדים), printed after his death in 1600, is considered as one of the main books of Jewish deontology. He also wrote a commentary on Tractate Bezah and Berachot of the Jerusalem Talmud.
The Piyyut (liturgical poem) Yedid Nefesh (ידיד נפש) was composed by Rabbi Elazar. (via wikipedia)