Frank Sinatra's Surprising Vulnerability Irresistible to Women, Book Says

Frank: The Voice

New biography reveals surprising turmoil behind those famous blue eyes.

Gene Simmons has nothing on Frank Sinatra.

The KISS frontman, legendary for the number of women he (says he) slept with, would have had a hard time keeping up with Sinatra in his prime, says James Kaplan, the author of “Frank: The Voice” (Doubleday).

The big difference? Sinatra never bragged about it.

“The women started coming at him from the beginning of his career. He was magnetic,” Kaplan told FOX411.com. “Despite the fact that Sinatra married in 1939, it didn’t matter. He gratefully accepted all offers, and there were hundreds and hundreds, if not thousands, of them along the way.”

So what was it about a skinny kid from Hoboken, NJ, that made women swoon?

“His vulnerability made him enormously appealing to women,” Kaplan said. “From the very beginning of his career, he found that when he would get up on the bandstand, if he put a little catch in his voice when he was singing one of his soft ballads, that the girls would just melt. So he learned to use what he felt naturally to attract women.”

“Vulnerability” may not be the first word that comes to mind when one thinks of the legendary Chairman of the Board, revered by friends and enemies alike as one of the toughest men in show business. But Kaplan says it was that vulnerability that was seat of Sinatra’s immense drive.

“He was kind of a damaged guy. He was damaged at birth physically. He was 13-pounds plus at birth. The doctor yanked him out with forceps, scarred up the left side of his face,” Kaplan said. “He was very self-conscious about that, self-conscious about being small, about being Italian-America, a guy who had a lot of neuroses. That vulnerability filtered into the songs, along with his absolute understanding and amazing, matchless ear for music, made him a singer like no other."

Despite his long line of lovers (and four wives), Sinatra had one relationship he prized above all others.

“Ava Gardner was the love of his life,” Kaplan said. “He first met her in 1941 when she was just 19 years old, and then they really got together in the late 40s, and that was when Sinatra left his wife and children for Ava Gardner.”

Gardner and Sinatra wed in 1951 (his second marriage, her third). “Frank: The Voice” covers Sinatra from birth to 1954, when he won his Oscar for “From Here to Eternity.”

“It’s about Sinatra as Elvis, 10 years before Elvis; as The Beatles 20 years before The Beatles,” Kaplan said. “He was the first national superstar.”

Click to buy “Frank: The Voice.”