On the summer weekend of July 22 and 23, 1966, the Family Dog hung Stanley Mouse and Alton Kelley's "Snake Lady" over the Avalon Ballroom door — poster FD-17, a woman's face wreathed in a coiling serpent, its lettering bending into that swimming, near-illegible Art Nouveau script Chet Helms's dancers had already learned to decode. The bill read Jefferson Airplane and The Great Society, and to anyone reading it a year later it would look like a printer's error, because those two names belonged, in the standard telling, to the same voice. They did not yet. This is the hinge, and it is worth standing still inside it.

In July 1966 Grace Slick was still the singer of The Great Society, the band she had formed the previous October with her husband Jerry on drums and his brother Darby on guitar. It was Slick's group that had been playing "Somebody to Love" — Darby's song, then titled "Someone to Love" — and Slick's own "White Rabbit," the Ravel-slow bolero she had built out of Bolero and Miles Davis's Sketches of Spain and a bad copy of Alice. Across the stage that night stood Jefferson Airplane, and their female voice was not Grace Slick. It was Signe Toly Anderson, the Airplane's original singer, who had cut Takes Off with them and would leave that autumn after the birth of her daughter. Slick did not join the Airplane until October 16, 1966 — Anderson's last night was the 15th, Slick's first the 16th — a full three months after this Avalon weekend.

So the poster records a genuine coincidence rather than a reunion: Grace Slick's present band opening for her future one. She was watching, from the Great Society's side of the room, the group she was about to enter. And she carried the freight with her. When she crossed over that October, "Somebody to Love" and "White Rabbit" crossed too, and on Surrealistic Pillow in 1967 they became the Airplane's — and America's — first psychedelic hits, songs now so fused to Jefferson Airplane that their Great Society parentage has all but vanished. In July 1966 that transfer had not happened. The Airplane on the Avalon stage did not yet own those songs; the woman who would give them away was singing them across the floor.

Above it all hung the Mouse and Kelley image, made the way the pair made everything that season: by raiding the visual attic. Kelley found the pictures, Mouse drew them true, and together they turned Victorian engravings and old advertising cuts into a new civic language for a scene that was, in the summer of 1966, still small enough to fit in one ballroom on two nights.