An inadvertent commentary on what made the late Dick Gregory special came through in the one-man IndyFringe festival show “Black in the Box,” which I saw at the Phoenix UndergroundSunday  afternoon.

Gregory pioneered direct talk about race in stand-up comedy, departing from the expectation that black funnymen would, for the most part, keep it light and well away from racial troubles.

In this disturbing, captivating show, Marlon Andrew Burnley devotes part of his overview of the African-American experience to the need to keep post-Emancipation troubles at arm’s length. The genesis of black entertainment — at first a matter of hard-won temporary relief from oppression, later formatted into minstrelsy to amuse whites — was just one of “Black in the Box”‘s memorable episodes.

The ghettoizing of the black man as an entertainer was among the confinements that Gregory burst through. Burnley similarly emphasizes the Jim Crow-era adjustments that had to yield to direct confrontations with white racism, whose effects persist.

The performer takes the audience from the horrors of capture and the Middle Passage into slavery. Escape under great risk toward the illusory promise of freedom is among the show’s many poignant scenes.

Burnley’s representative African-American drags a battered trunk around with him, drawing various props from it to mark each difficult stage of setbacks and advancement. The pathos of black contributions to the Union effort in the Civil War yielding to a long era of continued marginalization and disrespect is vividly displayed. Slide projections and a graphic soundtrack accompany his performance, wordless until near the end, when passionate civil-rights oratory is punctuated by an assassin’s gunshots.

To conclude the show, the performer speaks in his own voice, thus drawing his wide circle of implied narrative into a more personal orbit. The intimacy of such an ending keeps what has gone before from staying too much on the overview level. The waves across four American centuries of black punishment and pride that he embodies are so focused on his dancing and acting skills (plus the show’s creative cohesiveness)  that the artistic message remains uppermost.

We don’t feel we are in “Eyes on the Prize” or Ken Burns territory, but rather on a higher plane of urgent testimony, refracted through the use of a series of well-designed masks. Paul Laurence Dunbar’s poem “We Wear the Masks” clearly is an animating force behind this device.

There are plenty of documentary touchstones in the show, but the context in which they are set makes “Black in the Box” stand out among the festival’s more serious and adventurous offerings.