This is Jethro Tull's most famous song, but it was not released as a single. Ian Anderson told us why
: "Because it was too long, it was too episodic, it starts off with a loud guitar riff and then goes into rather more laid back acoustic stuff. Led Zeppelin at the time, you know, they didn't release any singles. It was album tracks. And radio sharply divided between AM radio, which played the 3-minute pop hits, and FM radio where they played what they called deep cuts. You would go into a album and play the obscure, the longer, the more convoluted songs in that period of more developmental rock music. But that day is not really with us anymore, whether it be classic rock stations that do play some of that music, but they are thin on the ground, and they too know that they've got to keep it short and sharp and cheerful, and provide the blue blanket of familiar sounding music and get onto the next set of commercial breaks, because that's what pays the radio station costs of being on the air. So pragmatic rules apply."