We are enjoying such a glut of musical theatre at the moment that you could be forgiven for asking, well, what other kind of theatre is there?

It's significant, therefore, that the musical piece that is the most original, beguiling, ambitious and surprising might well turn out to be Caroline, or Change at the National Theatre, a new production by George C Wolfe of the musical by Tony Kushner (book and lyrics) and Jeanine Tesori (music) that he first directed at the Public Theater in New York three years ago. The show moved on to Broadway, but closed after only 38 performances, despite several laudatory notices among a general critical disappointment.

The setting is small town Louisiana at the end of 1963, either side of the assassination of President Kennedy on 22 November. The year had begun with George Wallace in Alabama proclaiming “segregation forever”. In August, Martin Luther King galvanised the civil rights movement with his “I have a dream” speech at the Lincoln Memorial.

Coming from the other end of the spectrum, Kushner re-imagines his own childhood in this wider context of political change. Caroline Thibodeaux is the black maid in a starchy white dress in the basement kitchen of a comfortable Jewish household; little Noah Gellman is drawn to Caroline as a friend/servant/surrogate mother in the wake of his own mother’s death and his unhappiness with the pushy new stepmother, Rose, he has acquired from New York’s Upper West Side. His father has retreated into his music on the clarinet.

Rose allows Caroline to keep the change Noah habitually leaves in his laundry. Caroline’s mixed feelings about this escalate into a dramatic crisis when the change becomes a £20 bill. Caroline has three children of her own, and we meet them, too, coping with their mother’s dilemma. The generosity of the musical is reflected not only in the score – an astonishing amalgamation of American styles including blues, Motown, spirituals and klezmer – but also in the scope of the social canvas, which stretches in the second act to include a Chanukah dinner.

Even there, though, the show does not give up: Caroline’s daughter Emmie (stunningly well played by Pippa Bennett-Warner) is a cipher of hope and high spirits. The inanimate world of Caroline’s kitchen comes throbbingly alive, too, in the singing washing machine, the radio (a Supremes-style trio in gold lame sheath dresses and beehive hair-do’s) and Clive Rowe’s hilarious dryer, an exploding Little Richard. Rowe also sings the pivotal lament for the death of JFK, as a night bus.

Overseen by the ever-changing Moon herself (a gloriously turbanned, bluesy soul mother, Angela M Caesar), Caroline comes to a series of self-examinations culminating in a huge number that has been rightly compared to “Rose’s Turn” in Gypsy. Tonya Pinkins delivers this, as she delivers the rest of the show, with consummate artistry and a welling passion that tears the audience apart. This is a majestic performance, one of the greatest I have ever seen in the musical theatre.

Perry Millward is pretty amazing, too, as young Noah, one of three boys sharing the role, and the hand-picked cast also includes Anna Francolini as the new stepmother, and a superbly entertaining trio of grandparents: Ian Lavender (that “stupid boy” from Dad’s Army!), Valda Aviks, cosy as an apple strudel, and Hilton McRae. Magical design by Riccardo Hernandez, bathed in the crepuscular lighting of Jules Fisher and Peggy Eisenhauer, reinforces an unforgettable evening.

- Michael Coveney