The Guatemalan-born Perera, 64, has been hailed as the father of modern Sephardic history after publishing a multi-generational memoir of his family, "The Cross and the Pear Tree," that harks back to the 1492 Spanish expulsion of Jews.

Set against the backdrop of the Sephardic diaspora from the Mediterranean to Latin America, the book has been for Spanish-descended Jews what Alex Haley's "Roots" is to African-Americans.

Perera's commentaries on Central American affairs appear in national newspapers and magazines that include the New York Times, the Los Angeles Times, New Yorker Magazine and Atlantic Monthly. His subjects range from Mayan peoples and Guatemalan history to whales and the Loch Ness Monster.

"He is a man of intense and diverse interests, all connected by a search for a kind of mystical affinity or spirituality," said Bernard Taper, a retired professor from U.C. Berkeley's School of Journalism, where Perera is an adjunct professor.

An unidentified bystander found Perera near his car in the Lake Anza parking lot late last Thursday afternoon. He was conscious but disoriented and unresponsive, according to East Bay Regional Parks officials. The bystander summoned lake lifeguards to the scene and paramedics were called.

At Alta Bates, medical staff quickly determined that the writer's brain hemorrhage was inoperable and moved to stabilize him on life-support systems, Dr. Glen Petersen of Alta Bates said.

If Perera's condition didn't improve within 48 hours, he probably wouldn't regain consciousness, Petersen said Friday of last week. His condition didn't improve immediately, but by press time Wednesday he began to show signs of regaining consciousness.

Medical staff said this week that they have been unable to contact anyone in Perera's family. Friends and colleagues described the divorced- and childless-Perera as a loner who preferred writing about distant ancestors to talking about immediate family.

Several individuals recall the mention of an ill sister, who has lived in an institution for many years, and a traveling nephew, who is unreachable in Asia.

In the "The Cross and the Pear Tree," which was published in 1995, Perera cites some cousins in Guatemala. Finding them, however, could be difficult.

Meanwhile, the hospital has been flooded by phone calls from friends and well-wishers. Most didn't hear about Perera's stroke until Friday of last week because the writer had no identification on him when he was taken to the hospital.

Fortunately, he did have a business card leading hospital staff to the head of the National Association of Sephardic Artists, Writers and Intellectuals (Ivri-NASAWI), Jordan Elgrably, in Los Angeles. Perera and Elgrably co-founded the group two years ago to promote Sephardic culture.

From Los Angeles, Elgrably called the Jewish Bulletin, subdued and still shaken by the news.

"Victor Perera is the heart and soul of Ivri-NASAWI. If he doesn't make it, we are a bunch of young pups without a warrior," he said.

Elgrably said his partner is irreplaceable in the Sephardic academic community. His knowledge and passion for a history that is fading from living memory is unmatched.

Sephardic author Rebecca Camhi Fromer of Berkeley compared Perera's influence on modern Sephardic culture to that of Phillip Roth or Bernard Malamud on 20th-century Ashkenazi culture.

"Those of us who are first-generation Sephardim in America are trying to bring out the evocative things about our people," who comprise only 10 percent of U.S. Jewry.

The Ashkenazi singer of Sephardic songs, Judy Frankel of San Francisco, had met with Perera just a week before his stroke.

She described her friend as upbeat but distraught over the recent disappearance of his computer and a Guatemalan handbag that he carried.

Frankel said her five-year friendship with Perera began with a mutual admiration. Her singing reminded him of the way his aunt sang. Frankel revered the writer's work and shared with him a love of "nature, the clouds and the sea."

On the phone just a few days before the stroke, Perera talked enthusiastically about getting started on a book about whales that has been promised to the publisher Knopf, she said.

The two friends joined up last spring in Maui, where Perera was doing some of his whale research.

"He actually felt that he had communicated with the whales. He was absolutely positive that whales know about humans and want to be close to us," Frankel said.

Staff at Alta Bates have said that only family members, should they be located, will be allowed to visit Perera. All questions on his condition should be directed to Taper at (510) 654-6525.