As sprawling as their earlier epic The Dark Side of the Moon yet more focused, this 1975 jewel featured lengthy, left-of-center excursions (“Shine on You Crazy Diamond”) that were both majestic and reverent—along with a couple barbs thrown at the music industry ("Have a Cigar," "Welcome to the Machine"). It's also partly Pink Floyd’s anguished and glorious tribute to the gifted Syd Barrett—whose career with the band ended seven years earlier—and a moving set from top to bottom.