Last summer, as the debate over the Islamic community center near ground zero reached a fever pitch, longtime friends and former classmates Reza Aslan and Aaron Hahn Tapper were watching, fascinated.

“There were some Jewish organizations coming down on the rights of Muslims to build that center, and then some other Jewish organizations were coming out in favor of it — and criticizing those other organizations — and it just seemed like such a perfect example of how complex that relationship really is,” said Aslan, an internationally acclaimed religious scholar, writer and professor at U.C. Irvine. “That was a moment where we thought, ‘It’s time for this kind of book.’ ”

“Muslims and Jews in America: Commonalities, Contentions and Complexities,” a collection of essays by preeminent religious leaders, thinkers and innovators — eight of them Muslim, eight Jewish — is the result of a longstanding friendship between Aslan and Tapper.

As Ph.D. candidates in the religious studies department at U.C. Santa Barbara, the two were part of an informal group that turned out to be fundamental to their education.

“Every fourth Friday, a group of Muslim grad students and Jewish grad students would get together, break bread and just talk in a very real and sometimes confrontational way about the issues that divided us in the United States, and the way the Israeli-Palestinian conflict had infiltrated America in the post 9/11 world,” explained Aslan, who was born in Iran and grew up in the Bay Area. “So this issue of the commonalities and contention between America’s Muslim and Jewish communities is something we’ve been dealing with for a very long time.”

Following graduation, Tapper channeled those experiences into Abraham’s Vision, an 18-year-old organization that encourages Jewish and Muslim high school and college students to explore their identities through hands-on workshops, trips and political education.

Still, said Tapper — now a religious studies professor at University of San Francisco, in addition to the co-executive director of Abraham’s Vision — the collection seemed necessary.

“As someone who has worked in this field for over a decade, and been part of a team of Jewish and Muslim educators who wrote 115-lesson, 500-plus page curriculum for Muslim-Jewish programming, to the best of my knowledge, no book on contemporary Jewish American [and] Muslim American relations existed prior to this,” he said. “A number of people we reached out to responded by reaffirming what we already knew, that this project was a must.”

The book is divided into four thematic parts, with each containing four essays from members of the Muslim American and Jewish American communities.

Some are more academic case studies, such as a detailed look at what divides and unites the Iranian Jewish and Iranian Muslim communities in Los Angeles. Others are more personal, such as a series of correspondence between religion professors Aysha Hidayatullah from the University of San Francisco and Judith Plaskow of Manhattan College, on the topic of incorporating feminism into their respective religions.

The generational divide between both young Muslims and Jews and their parents plays an important role in understanding how relations are changing, according to many who lent their expertise to the book.

An essay on J Street explores how many Jews born after 1974, who feel removed from the Holocaust, have less and less personal connection to Israel over time — and how that impacts their relationship to the Middle East and to American Muslims.

“It’s very clear to me, based on my own observations since 2000 as well as a number of studies that have come out in the past few years by prominent Jewish American sociologists, that younger Jewish Americans are truly challenging the dominant discourse of older generations,” Tapper said.

The flip side of that for Muslims, Aslan said, is that many younger Muslim Americans are returning to their roots.

“The post-9/11 generation is far more explicit, far more open and even loud about their Muslim identity than their parents’ generation,” he said. “The immigrant generation, like many immigrant communities, generally put their heads down, went to work and tried to stay as quiet as possible. This new generation has absorbed their privileges as Americans … and many of them value faith in a way that is far more dramatic than their parents.

“That’s why we’re seeing young women who decide to take on the veil when their parents or even their grandparents didn’t,” he added. “We’re seeing young men who identify much more strongly as Muslims than their fathers.”

One major theme that stands out across perspectives: the fact that most Muslim American and Jewish American communities have more in common than they might realize.

“We’re both fairly equal numbers, depending on who you ask, we have a very similar historical experience of being demonized or made into outcasts, and we’re living in this incredibly diverse nation that nevertheless is founded on Protestant ideals,” Aslan said. “We would think that experience would bring these two communities together. Yet more often than not it is tearing them apart.”

Misconceptions on both sides are so deep-seated, Aslan noted, that he is often asked to begin speaking engagements at synagogues and Jewish community centers by reassuring the audience that he does in fact believe Israel should exist.

Both highlighting commonalities and challenging pre-conceived notions were central to the editors’ goal in putting the book together. As for the positive note on which the book ends — an optimistic piece by Rabbi Michael Lerner called “American Jews & American Muslims of Love” — Tapper acknowledged it was a very conscious decision.

“Many people falsely label Muslim-Jewish relations as entirely negative or bad,” Tapper said. “To paraphrase something Peter Geffen writes in the book’s afterword, positive stories about Muslim-Jewish relations are ‘no less significant or determinative than tales of violence and hatred. We continue to ignore them at our own peril.’

“I think that’s incredibly powerful, and for me, it sums up one of the main challenges,” he added. “What pieces of information are we open to integrating into our worldview, allowing it to change, and what pieces do we discard because they don’t support what we already thought?”

“Muslims and Jews in America: Commonalities, Contentions and Complexities,” edited by Reza Aslan and Aaron J. Hahn Tapper (228 pages, Palgrave Macmillan, $30)