Ray Thomas, a founding member...

...of the Moody Blues who played flute, sang and wrote a number of the band's songs, died at age 76.

From his obit in the New York Times (my emphasis):

In 1967 they released what is considered a progressive rock landmark, the album “Days of Future Passed,” which featured contributions from the London Festival Orchestra. It was one of the earliest albums to embrace the long, interconnected songs and musical experimentation that became key parts of the style in the early 1970s.

Mr. Thomas’s solo on the single “Nights in White Satin,” which became the group’s signature song, was one of the album’s defining moments.

1967? I distinctly remember this song being a hit when I was a freshman in high school.

Mr. Thomas said that when executives at Decca, the band’s label at the time, heard the album “they panicked: ‘Who’s going to buy this? It’s neither one thing or the other: it’s not rock ’n’ roll, and it’s not classical as such.’ ”

The label was right to be wary. “Days of Future Passed” did reasonably well in England but disappeared without a trace in the United States. It found an audience there only belatedly, when it was reissued in 1972 and broke into the Top 10. “Nights in White Satin” reached No. 2 on the Billboard singles chart.