Nat King Cole was an UNFORGETTABLE singer who rose to fame in the 1940s and 1950s. He was known for his smooth baritone voice and his ability to perform a variety of musical styles, including jazz, blues, and pop. He was one of the first African-American singers to gain mainstream success and was inducted into the Grammy Hall of Fame in 2000. His most famous songs include 'UNFORGETTABLE, ' 'Mona Lisa, ' and 'Nature Boy.'