Ammiel Hirsch and Yosef Reinman are dear friends. They respect each other's intellect and readily acknowledge their mutual love for each other as fellow Jews.

That's where the common ground ends.

Hirsch is a Reform rabbi and the executive director of ARZA/World Union, North America, the Reform movement's Zionist organization based in New York. Reinman is a haredi rabbi, talmudic scholar and prolific author in Lakewood, N.J.

Each has a problem with the other's interpretation of Judaism. A big problem.

Decades ago, leading Orthodox rabbinical groups forbade any official association with the Reform movement, although some exceptions were made regarding non-religious issues. The feeling was that an alliance conferred legitimacy, which the Orthodox, especially groups like the haredim, could never accept.

Yet somehow the two became close after being introduced by a mutual friend. They met casually at first, enjoying unending intellectual sparring. Eventually, they formalized their back-and-forth arguments into a co-authored book.

"One People, Two Worlds" is composed as a contentious philosophical dialogue between two polar opposites.

"It was a slugfest," says Reinman of the e-mail debate that blossomed into a rare collaboration between a Reform and an Orthodox rabbi.

How rare? So rare that Reinman abruptly withdrew from a joint three-week publicity tour after only two appearances.

He did so after the Council of Sages, a haredi governing body, issued a statement condemning the book and the publicity tour.

Hirsch continued on the road show alone.

A flurry of op-ed pieces blanketed the Jewish press following Reinman's departure, with Samuel Freedman lamenting "the arrogance and exclusionism of fundamentalists" and New York Jewish Week editor/publisher Gary Rosenblatt accusing Reinman of "bending to pressure from the religious right."

That's not how Reinman sees it.

Reached by phone, he says he voluntarily dropped out of the book tour following a joint appearance last month in New York (during which he told the audience it would be better to watch an episode of "The Sopranos" than to study Talmud with a Reform rabbi).

But he vigorously denies the council forced him to withdraw. "We don't tell individuals what to do," says Reinman. "I was free to do whatever I wanted. As much as I love Ammi Hirsch, this is not exactly what I want to do."

Reinman's explanation: Media critics and pundits misperceived the book as a "breakthrough" in Reform-Orthodox relations. "The media didn't bother to read the book," he says. "They didn't pay attention to what we said; instead they opened the floodgates."

That's when Reinman airlifted himself out.

For his part, Hirsch says he holds no grudges, and is in fact understanding of his friend's predicament.

"He's subject to pressures that are hard for people not in his world to fully appreciate," says Hirsch, in the Bay Area this month for the Union of American Hebrew Congregations' regional biennial in Santa Clara.

"Throughout the writing, I said to him from time to time, 'You know, Yosef, some rebbe is going to tell you at some point not to do this and you're not going to do it.'"

Hirsch does reveal more than a trace of lingering bitterness over having lost the opportunity to further exchange ideas with Reinman in public.

"You don't have to agree," says Hirsch "Strong disagreements should be encouraged, but we have to be able to relate to each other even when we disagree."

The carping flows both ways.

"Reform is not authentic Judaism," claims Reinman. "It's secular liberalism with a coating of shmaltz. This is something repugnant to people who follow the traditions of classical Judaism."

Meanwhile, as the old saying goes, there is no such thing as bad publicity. Sales of the book have been brisk, especially in the wake of the broad media coverage of the aborted book tour.

In fact, says Hirsch, sales are particularly strong in the Orthodox community. "I even heard it's being distributed in Israel," notes Hirsch, "in brown paper bags."