The Radak, Rabbi David Kimchi, was a medieval rabbi, biblical commentator, grammarian and philosopher. He was born in Narbonne, Provence in 1160. His father, Rabbi Yosef Kimchi, passed away when he was young, and he was brought up by his brother, Rabbi Moshe Kimchi.
The Radak saw himself mainly as compiler and summarizer. He created a dictionary of the Hebrew language, based on the work of his father as well as Rabbi Yonah ibn Yanah, but shows great innovation. His most famous work amongst the 7 books he wrote is his commentary on the Prophets. He was also an advocate for the Jewish people in debates with the church.
The Radak earned his living through teaching Talmud. He passed away in 1235.