  We construct the Zinn-Justin-Batalin-Vilkovisky action for tachyons and gauge
bosons from Witten's 3-string vertex of the bosonic open string without gauge
fixing. Through canonical transformations, we find the off-shell, local,
gauge-covariant action up to 3-point terms, satisfying the usual field theory
gauge transformations. Perturbatively, it can be extended to higher-point
terms. It also gives a new gauge condition in field theory which corresponds to
the Feynman-Siegel gauge on the world-sheet.
