The seafaring people of Madura, situated off the northeastern coast of Java, are one of the leading maritime groups in the Indonesian archipelago. They have played a major role in indigenous shipping, and since the second half of the nineteenth century their importance in this field has been second only to that of the Bugis and Makassarese. With their strong maritime orientation and outward economy, the coastal Madurese contrast strongly with the agricultural orientation of their near neighbours, the Javanese and the Balinese. The first part of this thesis presents the Madurese in historical context vis-his the Javanese and the maritime groups of Sulawesi. It then considers the various historical and cultural-ecological factors which predisposed the coastal Madurese toward seafaring as a livelihood, and which enabled them to eclipse their former rivals along the north coast of Java. The main seafaring centres of Madura during the twentieth century are identified, with these being in three distinct locations: the northwest coast, the southwest coast, and the eastern islands of Madura. Special attention is paid to the two major commodities carried by traditional Madurese vessels, salt and cattle, leading up to a more detailed consideration of the major transport commodity from the 1960s until the present, timber. The second part of thesis focuses on the role of the Madurese in the Java Sea timber trade. A key aspect of this account is the struggle between timber importers and the state. The legal aspects of the movement of timber are explained, along with their economic significance for importers and vessel operators, and the changing degree of compliance with the law from the early 1970s to the much stricter enforcement after the mid-1990s. From the late 1990s until 2003 the focus becomes closer to reveal the inner workings of the timber trade, with special attention paid to the rise of 'wild' ports on the isolated north coast of Madura, as well as the difficulties faced by many Madurese vessel operators after the ethnic conflict in Central Kalimantan in 2001. The profitability and risks of the perahu operators and timber traders are explained, and career profiles of several prominent individuals are presented. The study ranges widely in its setting, including maritime villages around Madura, perahu ports in Java, and timber ports in Kalimantan. It concludes that the traditional approach to business of the Madurese is no longer appropriate, and that diversification and change of approach are now necessary. The maritime entrepreneurs of East Madura have in this respect been more successful than their counterparts in West Madura, and it is suggested that this difference is linked to historical differences between the two areas.