Dennis DeYoung is an American singer-songwriter, musician, and producer best known as the lead vocalist and keyboardist of the rock band Styx. His music style is characterized by a blend of progressive rock, hard rock, and pop, with theatrical elements and symphonic arrangements. DeYoung significantly contributed to the band's distinctive sound and penned some of their most successful songs, including "Babe," "Mr. Roboto," and "Come Sail Away." Despite leaving Styx in 1999, his influence in the band and the broader rock scene is evident, marking him as a key figure in the development of '70s and '80s rock music.