Note de contenu : Of all the prominent musicians born in Bohemia in the eighteenth century, none is surrounded with as much mystery and mystique as Josef Myslivecek (1737-1781), known as "Il Boemo" ("The Bohemian") in Italy among music lovers unable to grapple with his unpronounceable Czech name. Scion of a wealthy family of millers from Prague (and himself a master miller), he acquired training as a composer only in his twenties; nonetheless he quickly became one of the most talented composers active in late eighteenth-century Europe. Despite a composing career of only eighteen years, Myslivecek produced a large and diverse body of work: twenty-seven operas, eight oratorios, many shorter vocal compositions, about fifty symphonies, twenty-nine overtures, sixteen concertos, and one hundred thirty-four instrumental chamber works. Prodigious, successful, and resourceful, he lived most of his adult life as an itinerant composer in Italy, uninterested in employment at any aristocratic or ecclesiastical musical establishment. A friend of both Wolfgang and Leopold Mozart for eight years between 1770 and 1778, his dynamic personality ("full of fire, spirit, and life" according to Wolfgang) is vividly brought to life in the Mozart correspondence - and not only the praiseworthy aspects, but also the air of scandal that often followed him. Complete and accurate information about Myslivecek's biography and works has remained elusive for many years. The present study narrates his life in light of all available biographical documentation, offers analytical discussions of all the genres in which he composed, and for the first time presents catalogs of all his music fully detailing its sources, editions, and recordings. During much of the last century Myslivecek's contributions to music literature were largely forgotten outside the Czech lands, in part, it is argued, because of national biases. In this book Myslivecek's particular style of composition is approached more systematically, and his participation in the creation of what is now recognized as an era of "high classicism" in European art music evaluated more comprehensively than in any previous study. There is also a critical re-appraisal of Myslivecek's relationship with the Mozart family and of his place in Wolfgang's musical development. Some twenty-eight letters in the surviving Mozart family correspondence mention Myslivecek, and for no other composer did Wolfgang express such a degree of affection. Indeed, the full implications of their strong personal rapport invite revision of older assumptions about their standing with each other: through scrutiny of specific works by both composers, the author makes the case the Myslivecek was a distinctive compositional model for the young Mozart.