My parents didn't live in Ojai when I was growing up, but we visited the town every couple of years, usually at Christmastime—when we'd stud oranges with cloves, each puncture releasing a fine spray of aromatic oil, and my Auntie Marie would make thick, chewy-soft candied orange peels and arrange them in cut-glass bowls. In between visits, the memory that anchored Ojai in my mind was of the scent of orange blossoms in the cold night air—that and the trees, their bright fruit glowing among the dark green leaves, silently welcoming me back home.

They still do. And whenever I go, my dad squeezes fresh juice for me every morning, handing me the glass with a ''Here, Snooks''. It's so rich and thick that I have to add ice cubes to thin it down.

Oranges are easy to take for granted. Heaped in grocery-store bins next to apples and bananas, they're sturdy and plentiful and seemingly without season, and you could say that they're not exactly riveting—unless you're someone like me. I think oranges are extraordinary and terrific. I'm especially fond of valencias and navels, not only because they're the varieties my parents grow but also because their ubiquitousness means I can eat them every day. I love the sweet, tangy brightness of a good orange. It's the most optimistic of fruits—the one I want when I wake up in the morning.

I'm grateful that I live in this century, because in earlier times, I might never have tasted an orange. For most of its history, the fruit has been all but unknown to the average citizen. Native to southern China and first cultivated there about four thousand years ago, oranges made their way to Japan, India, Africa, into the Mediterranean, and across the Atlantic (Columbus introduced them to the New World), but they remained rare, relished mainly by emperors, bishops, and noblemen. In the late 1400s Charles VIII of France built the first orangerie—a gallery for sheltering oranges—and monarchs all over Europe followed suit. (The most magnificent belonged to Louis XIV at Versailles. It was a C-shaped building stretching 1,200 feet, filled with a thousand trees in silver boxes.) Not until the last century could the middle class indulge in oranges, and only in the early 20th century did they become common in America—thanks in large part to distribution by railroad. Today they are the most popular citrus fruit in the world, and Americans alone eat nearly 20 million pounds of them every year.

Until the 1500s, the sour—also known as the bitter—orange was predominate. Grown not for eating but for its decorative value and fragrance, it was also considered medicinal: In Renaissance Florence it was believed that oranges held in the hand could ward off the plague; and by the 16th century, European sailors had discovered, rather more accurately, that the juice of oranges (and other citrus) could prevent scurvy. Oranges were used occasionally in cooking in medieval Europe, but it wasn't until sweet oranges reached the Continent in the 1530s, imported from India and planted first in Portugal, that they began to be eaten on their own.

The first sweet-orange trees in America were probably planted in St. Augustine, Florida, by Ponce de Leon in 1513. Today Florida grows four times as many oranges as second-place California, which didn't get its first trees until the early 1800s—but 94 percent of Florida's oranges end up as juice, because they're more succulent than California's and also not as pretty; California's cold nighttime temperatures give its fruit a deep, brilliant hue.

The two orange varieties best known in America—the thinner-skinned summer-ripening valencia (the world's most widely planted variety) and the seedles winter navel—both have deep roots in California. Valencias, which most likely originated in Portugal, arrived—unlabeled—in both California and Florida in the mid-1870s, and acquired their name a few years later, when a Spanish citrus grower, upon visiting some California groves, declared, ''That is the Late Orange of Valencia.'' The navel was discovered by an American Presbyterian minister in Brazil around the same time; young trees ended up in Florida, where they foundered, and in Riverside, California, at the home of Luther and Eliza Tibbets, an ordinary couple who had requested three for their yard. Luckily the Tibbetses had the perfect climate for navels—and nurserymen as neighbors—and their trees produced gorgeous, sweet fruit. Today most of the state's millions of navels can be traced back to the Tibbetses' trees, one of which is still alive, replanted in a city park in Riverside. Even after 125 years, it still bears fruit that is reportedly delicious.

By the 1920s nearly all of Southern California was thick with orange trees. Groves stretched from San Diego to Ventura and beyond, and inland through San Bernardino, Riverside, and Imperial Counties. As California historian Kevin Starr put it, oranges were ''a symbol of all that Southern California promised—health, graciousness, the enlivening gifts of the sun''. But when real estate prices skyrocketed in the early 1960s, ranchers sold out wholesale, and the land sprouted tract homes and shopping strips instead.

Ojai is one of the few places in Southern California that has managed to hang on to its orange trees. As Tony Thacher, proprietor of Friend's Ranches, one of the valley's oldest orange ranches, explained to me, Ojai's fierce zoning laws, passed by the townspeople in the 1950s, are responsible. That's why, when you drive up into the mountains in spring and look out over the valley, you'll see a vista of trees—white blooms and orange fruit—in large swaths and small backyard patches. Ojai still lives amongst oranges, and I, for one, am glad.