He is more myth than man, the Babe Ruth of brainiacs. Who doesn’t know the name Einstein? It’s as much a word as it is a name, a synonym for genius.

Apart from his celebrated scientific work, though, who was Albert Einstein the man? That’s a relative question, one that nimble playwright Mark St. Germain explores with wit, historical veracity and theatrical verve in his one-act play “Relativity.” It can (and should) be seen through June 10 at Penguin Rep, a professional theater of consistently high quality in Stony Point, Rockland County. (For tickets and information, visit PenguinRep.org or call 845-786-2873.)

The premise of the piece is fact-based: In 1902, Einstein and wife Mileva had a daughter, Lieserl. After she contracted scarlet fever as a 2-year-old, there is no known trace of what happened to Lieserl.

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Using as one source of documentation the book “Einstein’s Daughter” by Michelle Zackheim—which does not solve the mystery of what happened to Lieserl—Mr. St. Germain flexes his muscular muse to speculatively fill in the gaps.

He has drawn a portrait that boldly challenges our perception of an unquestioned icon by posing the question, “To be a great man, must you first be a good one?” At the play’s opening reception, the author told me he spent 18 months researching Einstein before writing the play and that “nothing negative said about him is not true.” In other words, the bright light of his mind blinds us to a decidedly dark side, which this play explores most cleverly.

Don’t be fooled into thinking you’d be sitting through a slog about science or a scientist. Far from it. You’ll be on the edge of your seat. This is about life and how we choose to live it. It is eminently relatable to any theatergoer who likes to be enlightened and engaged as well as entertained.

The play’s title of “Relativity” is a pun, representing on the surface the scientist’s famous formula of E=MC2 (the basis of nuclear power), but it digs beneath the surface to illuminate dysfunctional familial relations that unfold before us to become the heart of the drama the author has conjured.

The setting is 1949, Princeton, N.J., in the modest house where Einstein (Robert Zukerman) lived and worked for 20 years, until his death in 1955 at 76. The finely-crafted Penguin Rep set, by scenic designer Brian Prather, depicts a charming yet functional and austere space where Einstein ideates and formulates.

The room is outfitted with a picture window, a blackboard chalked with math equations, a wastebasket of crumpled paper, an artist-style desk with a top and no drawers, twin sets of wall shelves full of books. On the wall are portraits of Einstein’s heroes, including Mahatma Gandhi and two legendary scientists, Michael Faraday and James Maxwell.

As the play begins, Einstein is visited in his study by a woman, Margaret Harding (Celeste Ciulla), who introduces herself as a newspaper writer assigned to interview him.

The third character is Miss Dukas (Susan Pellegrino), Einstein’s real-life confidante, who keeps house and shields him from the outside world of ceaseless curiosity-seekers.

It is a marvelous cast. Ms. Ciulla’s character drives the narrative, and the actor credibly balances a dual temperament of being fraught and forceful. She is facing a force of nature and proves herself up to the task, and then some.

Mr. Zukerman and Ms. Pellegrino affect personas, replete with skillful and wholly understandable German accents, that transport us fully into their rarefied world.

Together, the trio (all members of the professional stage union Actors Equity Association) navigates a winding path of emotions and revelations with delicacy and undeniable impact, a feat that holds the audience in its grip from start to finish.

The actors also have the good fortune of bringing to life a script by Mark St. Germain that manages to be both playful and provocative, compact yet constantly compelling.

They are in the eminently capable hands of director Joe Brancato, founding artistic director of Penguin Rep. Along with Andrew M. Horn, the theater’s executive director, you will not find in the Hudson Valley theatrical impresarios who are more passionate, enterprising and successful than these two. They are to the stage born. As Mr. Brancato quipped to the opening night audience, “Theater is art. Television is furniture.”

In the play, after Margaret Harding begins her questioning of Einstein, it’s clear she’s more interested in his family life than in his professional life. “I’d like to write about the Einstein no one knows,” she tells him. “Einstein the husband and father.” That opens a Pandora’s Box of revelations that are more than skin deep; she gets beneath his skin, and the sparks begin to fly.

We discover in short order that he has two sons and grandchildren; that he is not short on various prejudices, and not long on compassion. He also is a jokester of the first rank.

As the pieces of his character and his personality come together, the image in our mind of a veritable fantasy figure soon is brought down to earth by the seasoned craft and intellect of Mr. St. Germain. He exposes in “the great man” a surprising array of flesh-and-blood foibles that raise justifiable doubts about the credibility of our collective criteria for hero worship. Never wearing socks is a charming idiosyncrasy. Never paying attention to your kids is not.

Halfway through “Relativity,” a thinly-veiled secret emerges about Margaret Harding, and the intensity of the drama becomes jet-propelled by a new mass of energy, squared.

Along the rapid-fire journey, we are treated to a sampling of the fervently contrarian views held by the “pop star of science” on a range of high-minded subjects. Using Ms. Ciulla’s character as Einstein’s foil, the playwright pointedly challenges those views with convincing counter-arguments.

In this way, both Einstein and his interviewer weigh in on psychoanalysis, religion, adultery, the human cost of greatness versus goodness, goodness versus evil, family versus immortality. Instead of leaving a Broadway musical humming the tunes, we leave Penguin Rep going “Hmmm,” as fresh food for thought is digested.

The playwright also highlights Einstein’s gift for coining epigrams, some of which, Mr. St. Germain told me, may not be verbatim, but which he himself phrased, rooted firmly in his subject’s well-known beliefs.

“I condemn racism, lynching, and war,” says the play’s Einstein, adding, “I am clearly un-American.” Another is, “Coincidence is God’s way of remaining anonymous.”

One of his best-known observations also shows up here: “Imagination is more important than knowledge.”

Kudos to Mark St. Germain and Penguin Rep for having an abundance of both in bringing this gift to our region. If you are a fan of intelligent, riveting live drama that packs a lot of meaning about the human spirit into a non-stop 75 minutes, the decision to see “Relativity” is a no-brainer.

Bruce “The Blog” Apar promotes local businesses, organizations, events and people through public relations agency APAR PR. He also is an actor, a community volunteer, and a contributor to several periodicals. Follow him as Bruce The Blog on social media. Reach him at bruce@aparpr.co or 914-275-6887.