Jane Fonda's new book explores the wisdom and confidence that come with age.

At age 73, Jane Fonda is experiencing what she calls her Act III. Having had several careers (actor, activist, fitness guru) and marriages (to Roger Vadim, Tom Hayden and Ted Turner) and children (Vanessa and Troy), Fonda, now a grandmother, finds that “I am beginning to become who I was meant to be all along.”

In her new book, published today, Prime Time: Love Health Sex Fitness Friendship Spirit — Making the most of all of your life (Random House, 2011), Fonda shines a light on this phase of life, combining her own stories with insight and advice — from longevity experts, medical doctors, Zen practitioners and older women and men — about how this third act can be positive and meaningful.

Fonda’s humor and gratitude come through on every page, making the book a fun read, though some of the practical information about aging isn’t new. Not that Fonda hasn’t had her share of disappointment and depression on her road to becoming healthy and at peace with herself. (“I have known failures of all kinds: career failures, wrong paths taken, time wasted, relationships spoiled — the bumps along the searches and meanders of my life.”)

Today she views life as a staircase that offers new promises at every step, even in the face of physical challenges and decline. For a successful third act, she says, you need to envision how you want to live, and then strive to make that vision a reality.

But first, a taking stock is necessary, a “life review” that looks squarely at past traumas and early relationships, as well as all the subsequent choices — not to lay blame but to understand how self-perceptions were created, and to recognize behavior patterns.

In her memoir, My Life So Far (Random House Trade Paperbacks, 2006), Fonda detailed much of her life story, but here she tells of her handsome young father, actor Henry Fonda, who was rarely home and was critical of his daughter’s looks, and how she didn’t learn until long after the fact that her mother’s death had been a suicide. She admits to the painful realization of how much of a chameleon she was in her relationships with men, and how she revels in the continuing joy of being a mother.

But what makes this book enjoyable is Fonda’s genuinely fun personality, so that it feels like a long conversation with a smart and funny friend. Certainly she’s had a privileged life, but that didn’t save Fonda from suffering a lack of confidence and or keep her from making mistakes. Through self-examination and help from friends and professionals, she’s arrived at “positivity,” a term coined by researchers at the Stanford Center on Longevity that means developmental shift to humor, gratitude, giving up grudges, becoming creative and not sweating the small stuff — all key to a rich, deep Act III.

With this attitude in mind, Fonda reviews all the topics that aging people must address: finances, friendship, nutrition, spirituality, sex, death and, of course, exercise. Though most of the facts are not new, Fonda has accumulated so many encouraging perspectives from a wide variety of sources that her book is also a guide aging well.

What reverberates throughout is that Fonda finally has a confidence that was beyond her grasp in Acts I and II. “I have become a much more inviting and optimistic person since I entered my Third Act,” she writes. “Whenever someone tries to make me feel dopey about it, I remind myself of the findings of a 2002 study … which revealed that older people with a more positive attitude toward old age lived seven and a half years longer!”

Five lucky winners will win a copy of the book. Just enter to win by Aug. 31! How have you found more confidence in your own Act II or Act III?

Tags: actor, actor activist, Cinema of the United States, Entertainment/Culture, Henry Fonda, Jane Fonda, Peter Fonda, Prime Time, Roger Vadim, Stanford Center, Stanford Center on Longevity, Ted Turner, Tom Hayden, Troy, United States, Vanessa, Zen