Although his name doesn't appear in the acknowledgment of Bradley Shavit Artson's book "It's a Mitzvah! Step-By-Step to Jewish Living," the mayor of San Francisco gets credit for putting the author in the position of writing it in the first place.

"Willie Brown is the best teacher I had to become a rabbi," says Artson, spiritual leader of Congregation Eilat in Mission Viejo.

Da Mayor gets a mention on Page 7 of Artson's book as "the Speaker of the California State Assembly" back in 1981 when the author, a Harvard grad, toiled as Brown's legislative aide.

"He was a great man to work for," says Artson, a San Francisco native, during a phone interview from Southern California. "He supported me 100 percent, and taught me so much about how to speak with passion, about how to stand for something, build a community, bring people along with you. He's the master of that.

"And how to have fun doing it," he adds. "He's also the master of that."

Two years later, Artson enrolled in the Jewish Theological Seminary.

"It became clear [politics] was not the life I wanted to live," he says. "I was more interested in Judaism."

Several people had been pointing him in that direction, including Harvard's campus rabbi, Ben-Zion Gold, and San Francisco Congregation Beth Sholom's late spiritual leader, Saul White.

"Rabbi White sounded and looked like one of the prophets," says Artson. "He taught me a more traditional way to be Jewish and passionate."

When Artson was growing up in San Francisco's Richmond District, he was not as zealous. A "fervent atheist," as he describes himself in his book, he only agreed to confirmation at Congregation Emanu-El under Rabbi Joseph Asher's tutelage, because it would get him to Israel.

"It was a wonderful trip," he says, "but at the time, I was not religious and wasn't that involved."

But freshman year at Harvard had a way of opening him up to questions about everything. He began to ask himself why he had been resisting Judaism.

Gold challenged him to read the philosophy of theologian Franz Rosenzweig and attend Shabbat services for two months.

"I loved Conservative services," says Artson. "The way they studied, tradition was revered, but it wasn't the last word."

As he began embracing Judaism, a friend advised him to "go slow, and take it one step at a time." That advice, Artson writes, "forms the backbone of my Jewish experience and the perspective of this book."

"It's a Mitzvah" is laid out in easy-to-read chapters. The first three answer the question, "Why study Jewish law at all?" and the remaining 15 tell readers how to approach it.

Members of Artson's congregation helped edit the book. They read the chapters as he submitted them, letting him know what they didn't comprehend.

"Every time I gave way to a rabbinic temptation to write to impress professors," says Artson, they let him know, "Maybe this matters to you, but is sure doesn't matter to us."

Consequently, the book is in its second printing, having sold 10,000 copies its first year and a half in distribution.

"I get letters from people all over the country," says the author. "It's why I became a rabbi: to share passion for Torah and God and Judaism."