[There] is something curiously attractive about [Hair's] excessiveness (and vigor), its willingness to be both flamboyant and ruthless on behalf of its cause. The evening is a series of more or less salubrious shocks to the personality; and what keeps it steadily exhilarating is a kind of good-natured improvisatory humor that sweeps almost everything that might be offensive off the boards.

It is, in many places, a very funny show. A few laughs—the most dispensable ones—are one-liners, pure raggedy-end gags, which are not better, and sometimes are far worse, than the ones Guy Bolton or Dorothy and Herbert Fields used to write for standard musicals. Most are purely visual. Early in the show, Gerome Ragni … swings out over the audience's vulnerable heads on a rope, like Tarzan, while singing about his sixteen-year-old virgin mistress; Rado himself gets tarred-and-feathered before the performance is ten minutes under way...