For those policy-makers who would like to refresh their knowledge of the concept of extension, this is a practical guide to provide need- and demand-based knowledge and skills to rural men, women and youth in a non-formal,  participatory manner, with the objective of improving their quality of life. The function of extension may be applied to several subjects, both agricultural  and non-agricultural,  such as health; when it is applied to agriculture, it is called agricultural extension.