This introductory volume to a series of national reviews on the role of aquaculture in rural development comprises a global overview of rural aquaculture; and guidelines for individual country reviews. Rural aquaculture is defined as the farming of aquatic organisms by small-scale farming households using mainly extensive and semi-intensive husbandry for household consumption and/or income. Aquaculture originated over two millennia ago but it remains a relatively minor agricultural activity globally in comparison to agronomy and animal husbandry. Considerable promotion is required for aquaculture to fulfill its potential to provide significantly increased food, employment and income for the rapidly growing population of developing countries. Contrary to popular belief, this applies to most countries of Asia as well as to Africa and Latin America. A systems approach is required to effectively promote rural aquaculture. Conceptual frameworks are recommended to facilitate understanding of interrelated factors involved in socially and environmentally sustainable aquaculture production systems, outline the means to assess the potential of aquaculture to contribute to rural development, as well as the means to promote it where and when appropriate. The major constraints facing the promotion of aquaculture are often not technical. Rather they are the limited ability of developing countries to assimilate and adapt existing technology for rural aquaculture where it does occur and limited local capacity in education, research and development.