  We use a "twisted group algebra" method to constructively adjoin formal
radicals $\sqrt[n]{\alpha}$, for $\alpha$ a unit in a commutative ring spectrum
or an invertible object in a symmetric monoidal $\infty$-category. We show that
this construction is classified by maps from Eilenberg-Mac Lane objects to the
unit spectrum, the Picard spectrum, and the Brauer spectrum.
