Jethro Tull's first concept album, 1972's Thick as a Brick, was actually intended as wry sendup of the whole concept album phenomenon. But the follow-up, A Passion Play, was a more earnest (though far from humorless) stab at presenting a conceptual piece. That said, it's not essential to follow frontman Ian Anderson's lyrical narrative in order to enjoy the recording. In fact, it's the magisterial flow of the music that really propels the album-length suite; not only are there several instrumental sections, Tull as a whole had never been tighter. The band expertly navigate 45 minutes' worth of complex shifts in time signature, tempo, and dynamics on what remains one of their most sophisticated and musically nuanced prog-rock meisterwerks. For those who are curious, A Passion Play's story mostly concerns the afterlife journey of a man who's fit for neither heaven nor hell. But even if you don't follow the thread, Anderson's lyrical imagery is striking enough in and of itself to keep pace with the thrills and spills of the endlessly surprising arrangements.