A year to the day after the Charlatans opened the Red Dog, the scene they'd seeded was thriving back home - and on June 21, 1966, one of its most important early bands was midway through a stand at the Matrix, the small Fillmore Street club Marty Balin had opened in 1965 as Jefferson Airplane's home room. The band was The Great Society, fronted by Grace Slick - months before she would leave, that October, to join the Airplane and carry two Great Society songs into rock history: "Somebody to Love" (which the band had played as "Someone to Love") and "White Rabbit." The June 21 show (with Dan Hicks and Don Garrett on the bill) sat inside a June 21-26 Matrix run.

The poster, catalogued AOR-2.113, is a small-format Matrix piece - and a good example of why this era's art rewards a close look. At a glance the central image reads like military dog tags on a chain; look again and it's a capsule spilling its contents, a pill pouring out - a sly bit of period iconography for a band whose singer was about to make "White Rabbit" the decade's most famous song about altered states. It's the Matrix in miniature: no Bill Graham budget, no Avalon ballroom scale, just a clever handbill for a club show by a band on the verge.

The Great Society never broke out the way the bands around them did - they dissolved in the fall of 1966 as Slick left for the Airplane - but their Matrix residencies are where "Someone to Love" (written by her brother-in-law Darby Slick) and "White Rabbit" (hers) were road-tested before they became Airplane standards on 1967's Surrealistic Pillow. June 21, 1966 is one night in that brief, consequential window.