On Friday, September 20, 1968, the Family Dog's poster machine was promising San Francisco a heavyweight weekend at the Avalon Ballroom: the Steve Miller Band, the Chicago blues patriarch Muddy Waters, and the local A.B. Skhy Blues Band, wrapped in a Family Dog sheet catalogued FD-138. The card advertised a three-night run, September 20 through 22. It is a handsome poster, and for years it has been filed — incorrectly — among the Wes Wilson canon. The catalogs are clear on the point: FD-138 is the work of John O'Green (credited on Wolfgang's as "The West Will Sun Graffix / John O'Green"), not Wilson, even though Wilson bracketed it on both sides with FD-137 (John Mayall) and FD-141 (Grateful Dead). It is exactly the kind of near-miss attribution the archive has to guard against.

The poster tells one story; the calendar tells another. The best-documented event of that exact night was not at the Avalon at all but across the bay at the Berkeley Community Theatre, where the Grateful Dead headlined over the Steve Miller Band and Ace of Cups. The San Francisco Chronicle listed the bill that Friday, and the Dead's own archive preserves the evening (jerrygarcia.com); multiple soundboard recordings survive. The night's legend is a drum interlude: during "Alligator," two risers reportedly slid onstage bearing the tabla master Shankar Ghosh and the dumbek player Vince Delgado, who traded rhythmic cycles with the Dead's percussionists — an early public seed of what would become the band's lifelong immersion in world percussion.

That single Friday, then, holds a genuine bibliographic snag. Steve Miller's name is on both bills. The careful conclusion, argued by Corry Arnold, is that Miller "more likely did not play the Avalon on Sep 20," and that the FD-138 date is an advertised intention the band did not fully keep. A poster, after all, is a promise printed a week early, not a receipt — the FD-127 lesson in miniature, where the sheet, the catalog, and what actually happened can each say something different.

Set the attribution and scheduling puzzles aside and the FD-138 bill still captures a real moment. This was the Steve Miller Band of the "Sailor" era — the second album arriving that fall of 1968, the group already past its raw blues beginnings and moving toward studio polish. On the same card stood Muddy Waters, whose presence at a Family Dog dance hall is the whole subtext of the San Francisco scene: the ballroom bands were, to a one, students of the Chicago blues, and here was the source material sharing a stage with its acolytes. Whether Waters played all three nights or one, the pairing is the point — electric Delta blues feeding directly into the psychedelic ballroom, with the young A.B. Skhy Blues Band as the local link in the same chain.

So September 20, 1968 gives us two truths worth keeping side by side. The confirmed event is the Dead's Berkeley Community Theatre show, tabla risers and all. The famous artifact is FD-138, a John O'Green poster advertising a Steve Miller / Muddy Waters / A.B. Skhy weekend that the calendar only partly delivered. Both belong to the record; neither should be dressed up as more certain than it is. Across town the same night, Bill Graham's Fillmore West was in the middle of its own weekend — Albert King, Creedence Clearwater Revival, and Black Pearl on Rick Griffin's BG-137 — so a San Franciscan on September 20, 1968 had, in effect, three ballroom bills and a Berkeley theater to choose among on a single Friday.