We have been treated to a somewhat accidental and very unofficial Aaron Posner theater festival in Wisconsin for the past year and a half. It began when the Rep produced his stage adaptation of the Chaim Potok novel "My Name is Asher Lev" in the Stiemke Theater at the start of last theater season.

Posner, a Washington, D.C.-based director and playwright, staged his own piece, and it was brilliant. In early summer he went to Spring Green, where he directed a compelling production of "The Glass Menagerie," taking a slightly different expressionistic approach to the classic and giving it a new freshness.

Back at the Rep this year, Posner directed the superb "To Kill a Mockingbird" that had its run extended through Sunday. Last weekend, In Tandem Theatre joined the party, opening an exceptional production of another Posner adaptation of a Potok novel, "The Chosen." He collaborated with Potok on the script.

Ironically, Posner is a Madison native, but he was virtually unknown to Wisconsin theatergoers until Rep artistic director Mark Clements brought him here in the fall of 2010.

In Tandem's "The Chosen" proves that Posner didn't simply get lucky with "Asher Lev." He again demonstrates that he possesses the ability to transform fiction on the page to magic on a stage. Because novels and plays are shaped so differently, attempts to achieve that metamorphosis often disappoint.

Credit In Tandem and its co-founder and artistic director, Chris Flieller, for turning Posner's and Potok's script into a beautifully realized production that glows with sensitivity, intelligence and understanding.

First published in 1967 and set during World War II, "The Chosen" resonates with contemporary relevance. Two Jewish teenage boys are growing up in Brooklyn, separated by only a few blocks and major cultural differences. Although both are orthodox Jews, Danny is Hasidic and the son of a rabbi with a large devoted following, and Reuven is modern and the son of a Talmudic scholar.

Wearing distinctive 18th century Eastern European clothing and sidelocks, Hasidic men set themselves apart from more mainstream Jews. They do not engage contemporary culture.

Danny and Reuven develop an unlikely friendship that is severely tested by their fathers' dissimilar approaches to Judaism and being Jewish. The story follows them through high school and into college as the world-curious Danny struggles with his relationship with his stern father and the expectations that he will follow in his rabbinical footsteps.

This is played out on a momentous historical canvas that includes the death of President Roosevelt, the end of World War II, the revelation of the Holocaust and the rise of Zionism.

The Posner-Potok stage adaptation removed the book's secondary characters, tightening the focus to the two contrasting pairs of fathers and sons, and the writing is taut and dramatic. It speaks to our times, because an underlying tolerance of and respect for spiritual and cultural differences runs through the play. If only that were true in 21st century America.

The In Tandem production is pitch perfect, with elegant, exquisitely sculpted performances from its all-male cast. Bill Watson and James Tasse play the fathers with such fervent genuineness, we lose all sense that they are acting.

Eric Schabla (Reuven) and Andrew Bosworth (Danny) are equally real and credible as unusually bright young men navigating adolescence while trying to figure out what it means to be an American Jew during the 1940s. Matt Daniels effectively sets the theatrical table and watches over the action as the adult Reuven/narrator. He also provides a handful of comic caricatures of minor characters.

In Tandem's "The Chosen" vividly illustrates the depth of theatrical talent we have in Milwaukee. Don't miss it.