At home in Spokane, Washington, Sally Pierone works in her kitchen, dabbing and swirling bright poster paint onto paper. It's a method called spontaneous painting, something she learned in a workshop led by the French artist and teacher Michele Cassou. The idea is to let your mind empty and let your brush take over. "It's like a message from your unconscious," Sally explains.

For Sally, the images that emerge—some over a few hours, some over a few weeks—are often a surprise: a screaming baby inside a woman wearing an enormous red hat, a lost lover, a cruise ship dumping trash into the sea. Always, they are lessons in self-discovery. "My work is a self-portrait," she says.

Painting is hardly new to Sally. A trained artist, she lived abroad in the 1950s, exploring towns with friends and painting along the way—sidewalk scenes in Rome, a vibrant mural of American life for a Florentine cafe, portraits of children in Paris. She became art director for the Marshall Plan, managing projects promoting the rebuilding of postwar Europe.

Impressive, yes. But the witty, irreverent paintings shown here reflect the real Sally. Her work with Cassou seems to have unlocked a key, and the paintings haven't stopped—nearly 200 so far. They're featured in a brand-new book, Sally, a True Story: The Older Woman's Illustrated Guide to Self Improvement, written by Judy Laddon.

"I always thought, When I get really old I want to do art again," Sally laughs. "See? I've managed to pull that off."

As you'll see in this gallery of paintings [0], indeed she has.

For information on her book or to order giclée prints of her paintings, visit sallythebook.com [1].