The Moody Blues' early years were marked by a series of singles and EPs, including their debut single "Dumb on a Dumbie" (1965) and their first album, "The Moods of the Blues" (1965). However, it was their second album, "Days of Future Passed" (1967), that brought them critical acclaim and commercial success. Featuring the iconic song "Nights in White Satin," this album marked the beginning of the band's signature sound.