Exactly 40 years have passed since Jethro Tull’s over-the-top prog rock concept album Thick As A Brick was released. The album’s fictional narrator, a young English boy named Gerald Bostock, has grown old since then. So what happened to him in all this time, anyway? Any number of things can happen in a lifetime. The possibilities are basically endless.

That is the deceptively simple premise of the classic’s follow-up, Thick As A Brick 2. Credited to Ian Anderson, Jethro Tull’s frontman (purists are sadly missing Martin Barre, the band’s brilliant guitarist), Thick As A Brick 2 nevertheless harks back to the band’s roots in the wild excesses of the ‘70s. It’s big, it’s beautiful, and it’s downright batty when it wants to be.

Though the album is split into 17 different tracks, it is really best listened to as a single chunk, like its predecessor.

Lyrically, the listener follows the life of Bostock through its what-ifs, maybes and might-have-beens. Did he grow up to be a banker? A soldier? Maybe a televangelist, or a delusional bum? Or perhaps, worst of all, he grew into a soul-crushingly ordinary man, whose life slips away while he isn’t looking? The listener certainly doesn’t know, but drifting along through the glorious murk of Anderson’s words (some of which he speaks instead of sings) is half the fun.

The other half, of course, is the music. As with its predecessor, there are parts that feel like the backing tracks to children’s book readings. Mostly, these accompany Anderson’s forays into spoken poetry, which are enjoyable for some, but, understandably, not for everyone.

Detractors rest assured, though, that these strange interludes are setups for some heavy and pristine rock.

Tracks like “Banker Bets, Banker Wins,” “Shunt and Shuffle,” and “Kismet in Suburbia” can stand up against any of the hard rock offerings in Tull’s history. Tying the two together are folkish, dreamy sequences, the quintessential example of which is “A Change of Horses.”

If you want to rock from start to finish you’ll get a little bored. But if you don’t mind some calm waters between the rapids, the interplay between the two is flawless.

If you happen to be a fan of Jethro Tull or prog rock in general, trust that you have only to acquire this magical album to be nothing but happy for 53 minutes. Anderson has obviously aged, just as his fictional protagonist has, but there’s plenty of life and more cleverness yet in this old fox.

If you’re new to this scene but are brave enough to leave the commercial mainstream, give Thick As A Brick 2 a try. You may walk away hating it, but you’ll have a hard time claiming that it’s anything but a pure original.

And for any listener, but especially fans, the last 30 seconds are perhaps the best part of the album. You might hate yourself for thinking it, but you’ll find yourself admitting that there was no other way for Thick As A Brick 2 to end. Give it a listen to see what I mean.