The artistic legacy of Alphonse Maria Mucha (1860-1939), one of the founders of the Art Nouveau style, is both brilliant and bewilderingly diverse. Mucha is most famous for his Sarah Bernhardt posters and his magnificent decorative panels such as "The Seasons," works that continue to grow in popularity, despite the indifferent quality of most modern reproductions. To graphic artists and commercial designers, Mucha is praised for the innovative stylebooks that pioneered the use of Art Nouveau in commercial packaging, design, and ornament. But the primary element in all of Mucha's artistic...