Pinning down how Jews in the United States practice their religion can be tricky, since there are so many ways they define themselves. So, is there a way to corral the disparate pieces into a full picture of American Jews? Professor of American Jewish History at the Jewish Theological Seminary Jack Wertheimer says there is, and it’s precisely this diversity and constant state of innovation that gives him some hope in a future for U.S. Jewry.

Wertheimer lays out a generally optimistic view in The New American Judaism: How Jews Practice Their Religion Today (Princeton, Aug.). His overriding feeling is that it’s the ability of U.S. Jewry to innovate at the margins, then adapt the innovations into the mainstream, that is keeping Jewish practice fresh and vibrant.

“I’m less skeptical about the long-term future of denominational synagogues as some others are,” Wertheimer told PW. “They seem to be rising to the occasion and adapting.”

What that means is the big three denominations of Judaism—Orthodox, Conservative, and Reform—are not likely to disappear anytime soon, despite changes in the way U.S. Jews prefer to practice their religion. While Wertheimer focuses primarily on Jews who display a religious commitment, he acknowledges that there are many Jews in the United States who no longer practice Judaism or attend a synagogue, but still consider themselves to be “cultural Jews.” Yet, in the long run, a cultural identity is probably not enough, he said. “When it comes to the sustainability of Jewish life, I have serious doubts whether Jewish identity and commitments will be transmitted to the coming generations absent religious involvement.”

Wertheimer also looked at the large subset of American Jews who identify with Judaism as an historical and religious justification for social action, in what is known as Tikkun Olam. What he set out to do, however, was to get out of “elite” leadership circles and document “the actual experiences of people who are either attending synagogues or are attending the growing number of other places where Jewish religious congregating is taking place,” he said. He found that experimental practices are being adopted by the mainstream, keeping Jewish practice alive and relevant.

Practices like meditation and healing services, and small fellowships known as havurah, are catching on. Once considered a rebellion against conventional synagogues, “lo and behold within a short number of years hundreds of synagogues created small fellowships within their larger congregation and adapted the havurah model to the conventional synagogue,” he said.

Wertheimer is not impressed with statistics that say millennials are less religious than previous generations. Many have yet to practice what Wertheimer calls in his book “Judaism for peak moments,” or family friendly holidays such as Purim or rites of passage like bar and bat mitzvahs.

“We know from previous generations that one of the major circumstances that bring people to join synagogues is that they seek a Jewish education for their children,” Wertheimer said. “So if millennials are only beginning to have children in the latter part of their 30s, the likelihood is that they will not be involved with synagogues until they are somewhat older.”

There is no doubt that synagogues are changing, adapting everything from new kinds of music and choreography of the service to offering transliterated prayer books. “I think that that there still is an image of synagogues that’s based upon the post-World War II congregation, which was a far colder and more formal place. But it’s just not an accurate portrayal of what synagogues are like today,” said Wertheimer.

Younger Jews, he said, need to educate themselves about Judaism. Otherwise, “The best we can hope for is a very thin Jewish culture and a very limited impact that Judaism will have in the lives of individuals.”

Researching The New American Judaism has renewed Wertheimer’s own sense of hope for the future. “I’ve been involved in such writing about some of the problematic aspects of Jewish religious life and my book strives to re-balance that picture by also attending to those Jews who are involved,” he said. “What’s the nature of their involvement? What is attractive to them? What’s meaningful to them? What’s available to them? Jewish religious leaders are working very hard to help Jews find the synagogue to be a meaningful place.”