Alan Cranston, California's supposedly "low-key" senator, can shower and dress in three minutes.

That's the word according to a just-published biography of the Senate majority whip by Eleanor Fowle, a long-time activist in California politics. m"Cranston, the Senator From California," issued by Presidio Press in San Raphael, checks in as just a bit more authoritative than the usual authorized bio -- Eleanor Fowle happens to be Cranston's older sister.

Yesterday morning at the L'Enfant Plaza Hotel, author and brother, who's up for reelection this fall, breakfasted with the press to publicize the book. Someone asked Cranston if, well, he could really move that fast. The senator paused.

"If I have to," he said finally with a weak smile. "I don't like to waste time."

Up behind the podium, Fowle, who studied creative writing in the '50s with novelist Wallace Stegner at Stanford, briefly explained how she started the book six years ago as a two-to-three year project, never expecting it to turn into a "campaign biography."

Books on politicians by family members, of course, pop up pretty frequently these days. Sam Houston Johnson's book on brother Lyndon embarrassed its not easily embarrassable subject. Fowle, though, says she seeks only to inform.

"I wrote to find out about this rather mysterious brother of mine in the Senate," she explained, describing her brother as still "inscrutable" to her.

The California reporters who keep tabs on Cranston for the home crowd wasted no time themselves in tossing a few whiffleballs at the author.

"Your brother went so far in journalism," began one, referring to Cranston's early experiences as a foreign correspondent for the International News Service. "Why do you think he went wrong?"

Cranston, seated nearby with arms inscrutably folded, led the laughs, his pink cheeks lighting up.

Big sister handled the tougher pitches that followed just fine. One reporter remarked that she'd heard the description of Cranston as the Senate's whip, not the president's whip, many times before.

"These things are in your own pieces," Fowle returned, ever-so-sweetly.

"Could Alan do a better job as president than President Carter?" asked another.

"Murray," Fowle called out jokingly to Murray Flander, Cranston's press secretary, "I wish you'd tell me how to answer these."

"You don't have to answer that," the reporter shot back.

Some of the things the book recounts about Cranston's early career are not widely known. Back in the '30s, young journalist Cranston sought to warn America of Hitler's true intentions by publishing an inexpensive, unexpurgated edition of Mein Kampf. As a result, he had the apparently unique experience of being sued by Hitler for copyright infringement. Cranston lost.

The book follows him through his service in the Office of War Information during World War II, his work helping to found the California Democratic Council, his early political races in California and his election to the Senate in 1968. Initially reluctant to see the book published because he didn't think his life "merited a biography," Cranston eventually helped his biographer out with 40 cartons of material and taped recollections. Fowle says he exercised no editorial control over the book except to correct factual errors.

"He wanted to add things, not delete them," she recalled.

Now the only thing left is to find readers; 7,500 copies have been printed and Eleanor Fowle, who has a novel and several short stories in that famous trunk writers always have, hopes many more copies of the book will be needed. Even if that happens, however, neither she nor her brother expects the book to have much impact on his campaign.

"Only if there's something terrible in it that someone exploits," said Cranston, not appearing much afraid of that prospect. Surrounded by California reporters eager to have their own copies signed after the breakfast, Cranston was thinking like a writer.

"I thought the best way to promote the book would be to sue her."