Naul is a South Korean singer and member of the four-member soul music group Brown Eyed Soul. In 2001, Yoon Gun and the group Brown Eyes released their first album, [Brown Eyes] and the title song "Already One Year" was popular with Yoon Gun's melody-making ability and Naul’s explosive vocals. They also formed Brown Eyed Soul with Jung Yup, Sung Hoon, and Young Jun, capturing the public with their first album, [Soul Free] and the 2007 album, [The Wind, The Sea, and The Rain] and began to establish themselves as solo artists by releasing the remake album, [Back To The Soul Flight] and the first solo album, [Principle Of My Soul]. As soon as the solo album was released, it swept various music charts, and continued its activities with its second full-length album [Sound Doctorine] and single album [Soul Pop City] to show public popularity, ability as a vocalist, and ability to digest as a song maker. Recently, Naul has released a ballad project called [Ballad Pop City], where Sung Si Kyung, TAEYEON, and Naul participated in singing, showing steady progress.