Rav Avraham Yitzchak HaCohen Kook, known as the Ra'ayah, was born on 16 Elul 5625 (7 September 1865) in Griva, today part of Daugavpils in Latvia, the eldest of eight children. His father, Rabbi Shlomo Zalman HaCohen Kook, had studied at the Volozhin yeshiva, while his maternal grandfather was close to the Tzemach Tzedek of Lubavitch.

As a youth he studied in Lutzin under Rabbi Eliezer Don Yichya, and before the age of twenty he received semichah from Rabbi Yechiel Michel Epstein, author of the Aruch HaShulchan. In 5644 (1884) he became engaged to the daughter of the Aderet, Rabbi Eliyahu David Rabinowitz-Teomim, and then studied for about a year and a half at Volozhin under the Netziv, whom he regarded as his principal teacher.

In 5648 (1888) he became rabbi of Zeimel, and in 5655 (1895) of Bauska. On 28 Iyar 5664 (1904) he arrived in Jaffa as rabbi of the city and of the agricultural settlements; this was the most prolific period of his writing. Caught in Europe by the First World War, he stayed in Switzerland and then served as rabbi of the Machzikei HaDas community in London. Returning in 1919 as Ashkenazi rabbi of Jerusalem, he established the Chief Rabbinate and in 1921 became the first Ashkenazi Chief Rabbi of the Land of Israel. He also founded and headed the Central Universal Yeshiva, known as Mercaz HaRav.

A halachic authority, thinker and kabbalist, he is considered one of the fathers of religious Zionism. He supported agricultural settlement and defended the heter mechirah for Shemittah in his book Shabbat HaAretz. He placed unconditional love among Jews at the heart of spiritual and national renewal. His writings, including Orot, Orot HaKodesh, Olat Re'iyah and Ein Ayah, have deeply shaped Jewish thought.

He passed away in Jerusalem on 3 Elul 5695 (1 September 1935), shortly before his seventieth birthday, and is buried in the Mount of Olives cemetery.