The pinnacle of prog rock - Jethro Tull "As Thick as a Brick"

It must have been an amazing thing back in 1972 for a band to release a rock album that not only included a flute, a harpsichord, a lute, and strings, and adding timpani to the percussion, but that also had only one song, spread over two sides, and lasting almost 45 minutes.

And not only that but, at a time when music often stripped down to its rawest elements, Jethrol Tull's Thick as a Brick heaped theme upon theme, mixed them in with each other, stacked them on top of each other, turned them around, inside out and upside down, discarded them and then brought them back again, made audacious leaps from one key to another, and from one time signature to another, as if they were trying to outdo even Bach at his most musically complex.

So it could have been a complete flop - and probably would have been were it not for the way the music, with all its complexity and epic scale, draws you in by the simplest of approaches: by just sounding irresistably good. Its rhythms are hypnotic and catchy, its dry tonality is unadorned and immediate, despite all that's going on within it. It's music that feels like you should have heard it before, even if you haven't.

The music wafts between rock and folk and classical, at times sounding almost like Irish dancing, with its jaunty flute, at times like electrified Mahler, with innocent tunes transposed into minor keys and given a hint of grotesquerie, at times as uncompromising and dark as anything to have emerged from the heaviest and hardest rock, aggressive and dense, with guitars screeching and riffing against raging percussion.

And it is played just so incredibly well - listen to the precision of the drumwork, the tightness of the ensemble, the way nothing seems to pause for a breath, the way instruments poke their head in here and there, to just add a line or two at the right time, as we are taken through the strange tale of poetry and war, and of the falsehood of modern capitalist values.

Thick as a Brick is one of the earliest, but still one of the best, things ever to have emerged under the banner of "prog rock". It takes you on a whirlwind journey, so rich in music and ideas, that, when it finally comes to a rest at the end, you just want to go back to the start and do it all over again. And it's a journey worth taking many times because there will always be something in the landscape that you are sure to have missed before.