The roots of Inverness resident Laura Alderdice’s new children’s book reach back to Puerto Vallarta, circa 1970. Ms. Alderdice was living on the roof of the home of Roberto Perez-Rubio, an artist she met while working at Berkeley Arts. In the afternoons, she learned the language with Mr. Perez-Rubio’s children, Elga and Erika, and played folk music; in the mornings, she took her Sunfish, a small sailing dinghy, out in the Bahía de Banderas, hoping for an invitation onboard a yacht. During this time, she wrote five songs, inspired by the creativity of the Perez-Rubio household. The songs turned into children’s books, which Ms. Alderdice subsequently lost. Five decades later, the books resurfaced in her attic, along with her other writing from those days. This summer, she decided to publish one “just for fun.” Her book, called “A Joy We Spent,” will soon hit the shelves of Point Reyes Books. Written with a sing-song grace, it follows a diverse group of kids on a sailing adventure with magical explorations along the way. They find underwater friends, tickle trees and discover new perspectives through their pinwheels, all while sailing and playing on the beach. “There are a couple elements of philosophy in here, which is to stay playful and see the world with children’s eyes,” she said. Ms. Alderdice, who has a music degree in flute and composition and plays in the local band Tomales Bay Mudflats, plans to write “a simple melody that a child could sing” to accompany the book (she welcomes anyone who wants to help). Four years ago, Elga and Erika reached out to Ms. Alderdice. Both women live in the Bay Area now and have copies of the book that they share with their children and grandchildren. “If I hadn’t met the Perez-Rubio family, my life would have been very different,” Ms. Alderdice said.