Pancho Barnes was a force of nature, a woman who lived a big, messy, colorful, unconventional life. She ran through three fortunes, four husbands, and countless lovers. She outflew Amelia Earhart, outsmarted Howard Hughes, outdrank the Mexican Army, and out- maneuvered the U.S. government. In The Happy Bottom Riding Club , award-winning author Lauren Kessler tells the story of a high-spirited, headstrong woman who was proud of her successes, unabashed by her failures, and the architect of her own legend.          Florence "Pancho" Barnes was a California heiress who inherited a love of flying from her grandfather, a pioneer balloonist in the Civil War. Faced with a future of domesticity and upper-crust pretensions, she ran away from her responsibilities as wife and mother to create her own life. She cruised South America. She trekked through Mexico astride a burro. She hitchhiked halfway across the United States. Then, in the late 1920s, she took to the skies, one of a handful of female pilots.          She was a barnstormer, a racer, a cross-country flier, and a Hollywood stunt pilot. She was, for a time, "the fastest woman on earth," flying the fastest civilian airplane in the world. She was an intimate of movie stars, a script doctor for the great director Erich von Stroheim, and, later in life, a drinking buddy of the supersonic jet jockey Chuck Yeager. She ran a wild and wildly successful desert watering hole known as the Happy Bottom Riding Club, the raucous bar and grill depicted in The Right Stuff.          In The Happy Bottom Riding Club , Lauren Kessler presents a portrait, both authoritative and affectionate, of a woman who didn't play by women's rules, a woman of large appetites—emotional, financial, and sexual—who called herself "the greatest conversation piece that ever existed."