With their third album, 1970’s Benefit, Jethro Tull mastered their blend of English folk and hard rock as the acoustic textures build to electric frenzy in smooth transition. Yet, paradoxically, it’s still a tug of war between singer Ian Anderson’s flute and Martin Barre’s electric guitar, and this deliberate precise tension creates the band’s trademark musical drama around their elliptical riffs. The band’s frightening dexterity threatens to run off the rails at certain high octane instrumental spots (“Son”), but the songs are kept in tight focus. Anderson’s vocals are immediately recognizable throughout — slightly dismayed and always seemingly armed with a stern warning to future generations. Then again, he sneaks in an unusual tenderness (“For Michael Collins, Jeffrey, and Me”) in the quieter moments. At this point, Tull were essentially writing their own playbook, having jettisoned their early blues rock for an eclectic mix that — the influence of Rashaan Roland Kirk on Anderson aside — can only be labeled Jethro Tull music, though it would be their next release, Aqualung, that would become their signature. The expanded edition includes several bonus cuts and superior sound that highlights the band’s impressive chemistry.