On a white restaurant tablecloth in San Francisco, under the glow of a stained-glass dome ceiling with images of laurels, fleur-de-lis, and a ship, rested a portion of metal the size of a shallot. Around it, three men were having lunch one day in the summer of 2018. Jacques Vallée, a French information scientist, was explaining to Max Platzer, editor of a top aeronautics journal, how the metal had come into his possession. The story wound back more than four decades, he said serenely, to an unexplained episode in Council Bluffs, Iowa.
