What makes Voices in the Sky by The Moody Blues notable?

'Voices in the Sky' is significant for its role in cementing The Moody Blues as pioneers of the progressive rock genre, showcasing their unique fusion of rock with classical elements. The album contributed to their rise in popularity during the late 1960s, as they began to receive critical acclaim and commercial success, further influencing subsequent artists in the genre. Released on June 28, 1968, 'Voices in the Sky' marked The Moody Blues' artistic evolution following their groundbreaking album 'Days of Future Passed'. By this time, the band was transitioning from their earlier rhythm and blues roots into a more sophisticated blend of rock and orchestral music, solidifying their place in the burgeoning progressive rock scene.