In recent years there has been a marked advance in our understanding of Indonesian seas oceanography. This progress is a result of the growing interest of the oceanographic community in the unique characteristics of these tropical seas (see Gordon, this issue) and the support and openness of the Indonesian government to international scientific collaborations. The pace of research is also accelerating due to the application of new technologies (in situ observational methods and satellite imagery) and by increased communication among scientists brought about by the Internet. In the early days, studies of the ocean were made for navigational purposes. Increasingly, the economic importance of marine resources is being recognized and climate prediction encourages continued research.