The first time Alan Dundes saw a Shabbat elevator in an Israeli hotel, an unusual thought crossed through his head: "Wow, it looks too small to have a service in there."

When a hotel employee told Dundes what a Shabbat elevator really is — an automatic lift that allows Orthodox Jews to ride up and down without pushing any buttons — the U.C. Berkeley anthropology and folklore professor's reaction was understandable: He laughed.

Then he got serious.

The ingenious circumvention piqued the interest of the world-renowned folklorist and inspired him to learn more about Shabbat customs — and how to get around them. The result was the professor's new book, "The Shabbat Elevator and Other Sabbath Subterfuges."

Dundes, a self-described secular Jew ("I was never a fountain pen," he quips), has researched anti-Semitism, blood libel claims and even Jewish mother jokes. But never before has he undertaken a "full-length treatment" on Jewish culture.

His verdict: All cultures have restrictive customs — but nobody hurdles them with quite the aplomb of the Jews.

"Surely there are circumventions in all cultures. In cultures where you're not allowed to see your bride before you get married, I'm sure there are ways of peeking a view. All people need to find a way to get around the restrictive rules of the society they're in. What I'm trying to suggest is that Jews have developed it to a fine art. They really have it down pat," he said.

Paraphrasing Sigmund Freud's "reality principle," Dundes points out that "we all can't eat whenever we want; we're all restricted by whatever society we live in and whatever the rules are. The rules are different in different societies — but I don't know anyone else who pre-tears toilet paper."

Citing the Torah and rabbinic observations, seasoned with a generous helping of Jewish jokes, Dundes highlights the dazzling complexities behind the activities fervently religious Jews are forbidden to undertake on Shabbat and the methods of partially getting around the rules.

Regarding the Shabbat elevator, the touchstone of the entire book, Dundes discovered that Jerusalem's Rabbi Yitzhak Halperin has devoted no less than 16 years to crafting a workable Sabbath elevator. Among Halperin's key gripes is that any lift in which a passenger's weight is "a critical factor" in its descent is unacceptable for Shabbat use.

The use of a key on Shabbat is questionable, Dundes writes, unless, of course, the key doubles as an article of clothing, such as a tie tack.

And then there's shinui. This principle states that if one must undertake an activity on Shabbat, it is best do it in an unusual way. For example, one might press an elevator button with his or her nose, tear a piece of toilet paper with the elbow or carry an item with the back of one's hand.

Minutely organized rules on how to circumvent Shabbat customs have served Jews well through most of recorded history, according to Dundes.

"Jews in the diaspora have, essentially, had to find a way out of no way, as Zora Neale Hurston said. There have been so many restrictions on what Jews could do. The ability to find a way around it has stood Jews in good stead whenever faced with irrational and absurd regulations," he said. "There are jokes about that; if there was a flood, Jews would learn to breathe underwater. There are all kinds of jokes about Jews' ability to survive."

On the other hand, behavior that could be perceived as weaseling out of the spirit of the law may have contributed to negative Jewish archetypes.

"When people get wind of these things [Shabbat circumventions], it confirms the stereotype of Jews being devious, the shyster lawyer," said Dundes. "Jews can bend the law and find a way; get a smart Jewish lawyer and you'll get off."

Using Freudian arguments, Dundes speculates on the origins of many Jewish customs. Some hail from what he describes as an extreme — if not obsessive — desire for cleanliness and purity, and the Torah's well-documented aversion to contact with human and animal excrement. The professor believes this aversion in part explains the avoidance of pigs and the hindquarters of certain animals.

Employing Freud's "money-feces equation," Dundes argues that perhaps the ancient aversion to waste explains rules forbidding the handling of money on the Sabbath (and for that matter, led to the creation of such phrases as "stinking" or "filthy" rich or "rolling in money").

Dundes acknowledges that his arguments are often highly conjectural. Plus, "if you're anti-Freud, you're certainly not going to like it." Still, the professor hopes to ignite discussion with what he describes as "a great learning experience for me."

And, following a close exploration of Judaism and Jewish custom, he's off on a new challenge.

"I'm on to the Koran now," he said with a laugh.