No one ever speaks of a “lapsed Jew.” Jews who attend no synagogue, who don’t know a word of Hebrew, who may be married to Gentiles and have Christmas trees in the house, will still tell you that they “feel” Jewish.

But what kind of Jewishness is this? Lisa Schiffman, a Bay Area copywriter in her mid-30s, is struggling to find out.

Generation J by Lisa Schiffman (HarperSanFrancisco, $18)

Schiffman and her peers make up what she calls “third-generation Jews” (of which I’m one). Our grandparents arrived in this country with accents and Old World practices intact. Our parents typically fled their traditional upbringing for a resolutely secular life in the suburbs. And now we, raised with little or no Jewish education, adrift in the most assimilated society our people have ever known, struggle to come to terms with an identity we can’t quite embrace or escape. “Call us a bunch of searchers,” Schiffman writes, with copywriter flipness. “Call us post-Holocaust Jews. Call us Generation J.”

In this admirably honest yet strangely irritating account, Schiffman describes her own effort to reconnect with Judaism. She begins, promisingly enough, at the time of her wedding. Like many secular Jews, she feels drawn back to the tradition at a moment of life change. “For the first time in memory, I wanted to acknowledge that I was Jewish,” she writes. “I wanted to be met with open arms . . . I wanted in.” But no rabbi will marry her to a Gentile husband, especially when they have no intention of keeping “a Jewish home.” (In the end, Schiffman has to settle for an opera singer who played a rabbi in the movie Goodbye Columbus.)

The experience leaves her wondering why Judaism seems to have no place for a marriage like hers. “We and others like us were part of a Judaism that no one had yet named,” she decides, and sets out to “continue the work of creating Judaism” by finding a path for ambivalent Jews like herself.

Schiffman has written a highly personal, pitch-perfect book for the millions of Jews who are uncomfortable with God, skeptical, and secular, yet still moved by “spiritual” aspirations. Each chapter finds her exploring another dimension of Jewish thought and practice in both its New Age and traditional varieties: visiting a Jewish meditation center; attending Rosh Hashanah services with her irreligious parents; immersing herself in the mikvah, or ritual bath; and grilling an array of rabbis and thinkers about the more troubling aspects of the faith.

In language both lyrical and crass, she bravely lays bare her own unease about Jewish identity and her frustration with the fusty, rule-bound nature of traditional observance, while also managing to uncover layers of personal meaning within Jewish history and ritual. The Jewish dietary laws, for instance, become for her a lesson in achieving “an intensity of awareness,” in finding the extraordinary within the mundane.

Unfortunately, the frankness of Schiffman’s book is also the source of frustration for the reader. She often seems less interested in learning about Judaism than diving ever deeper into her own fascinating psyche. “When was the last time I’d played with the range of who I am?” she wonders, in a chapter in which she decides “to live for a moment as though God just might exist.”

As Schiffman shops around to see what Judaism has to offer, she seems particularly averse to any part of the tradition that might put a demand on her—which is inconvenient, since the notion of a covenant, of an obligation, is probably the most important idea in the entire religion. The mitzvot—Judaism’s ethical demands and prescriptions for living—turn up in Schiffman’s spiritual wanderings only long enough for her to dismiss them as too much work.

By contrast, she is always happy to embrace the groovy, unchallenging messages offered up by New Age interpreters of the tradition. The mikvah, she is told, is about “liking your body.” The Jewish Sabbath is “a time to suspend judgments of yourself. . . . Know that you are perfect.” When Schiffman tries to seek out God by overcoming self-consciousness about her singing voice, she learns, inevitably, that “There are no bad voices. There are no ugly voices, no out-of-tune ones. . . . All voices are beautiful.”

By the end, Schiffman manages to make peace with her conflicted feelings. “My Judaism was a trajectory,” she decides, “a continuum. . . . Some days it was a brain-based religious thing, full of demands for logic and a grapple with text. Some days it was a feeling of identity. Some days it was in my body, my marrow. . . .” She expresses her newfound sense of being “Jewish by choice as much as by birth” by getting a Star of David henna tattoo applied to her back.

But where does this leave Judaism, the 3,000-year-old legacy she has been helping herself to over the previous 10 chapters? Typically, this is not a question she bothers about. Schiffman’s only perceived responsibility is to be true to herself (which probably makes her a fitting spokesperson for Generation J).

Despite her journey, Schiffman’s ideology doesn’t really seem to have changed much from what it was when she began: your basic post-’60s, judgment-free, “I’m beautiful the way I am” philosophy that is no more Jewish than Hillary Clinton. The notion that there is something peculiarly post-Holocaust about all this Aquarian introspection is certainly the most absurd idea in the book.

Lisa Schiffman will be appearing at the Museum of History and Industry on October 21.