In 1948, New Orleans veteran trumpeter and singer Louis Prima stumbled into a young girl named Keely Smith. She was barely a performer at all, almost half his age, destined for a relatively quiet life; their encounter was pure coincidence. But they went on to invent ''The Wildest,'' the most exciting and successful lounge act Las Vegas has ever seen, an act that became one of the hottest in the U.S. in the late 1950s and early 1960s. Their records were hugely popular, and they were courted by Frank Sinatra, Ed Sullivan, Robert Mitchum, and other well-known entertainers of the day. Their professional success helped bring about the rise of Las Vegas as a mecca of American entertainment. Their love story ended soon after they helped usher in John F. Kennedy's presidency--singing ''That Old Black Magic'' for him at his inauguration--but their influence is still evident. And Keely still draws SRO audiences to her nightclub appearances. Now, on the occasion of Louis Prima's 100th birthday, comes the first book on this duo, illustrating not only one of show business's greatest love stories but also the Vegas milieu in which they reached the pinnacle of their success.