ר”דק – ר’ דוד קמחי – R. David ben Yosef Kimchi (c. 1160-c. 1235) lived in Narbonne, Provence (southern France) and is best known for his Tanach commentaries to Bereshit, Neviim, Tehillim, Mishlei, and Divrei Ha-Yamim. Radak was the son of R. Yosef Kimchi, a Sefardi émigré to Provence, notable as an early translator of rationalistic works from Judeo-Arabic into Hebrew. He was the brother of Remak, R. Moshe Kimchi, also an exegete and grammarian, and to whom Radak refers as his teacher.
Radak was also known for his work on Hebrew grammar, the Michlol. The Michlol has two parts, the first being the grammatical treatise and the second being a lexicon. However, these two parts ended up being transmitted separately, the grammar becoming known as “the” Michlol, and the lexicon becoming known as Sefer ha-Shorashim. He also wrote the Et Sofer on the Masoretic notes to Tanach.