This is a festive drink that's basically a Manhattan with a champagne float. It was invented by (and named for) "Cocktail" Bill Boothby, the first native San Francisco bartender to publish a cocktail book: 1891's American Bar-Tender. The Boothby wasn't in that book, however. H. Joseph Ehrmann of Elixir found out about it in Bill Boothby's 1930 obituary in the San Francisco Chronicle, where it was called out as Boothby's signature drink. Ehrmann has (so far) been unable to track down a historical recipe, but he does know that Boothby's version of a Manhattan was a 50-50 mix of whiskey and sweet vermouth, so he's based this recipe on those proportions with an orange twist added as garnish.