ISYA typically last about three weeks and attract roughly twenty students at the Master of Science level. About half the students are from the host country, the others from neighboring countries. ISYA are initiated by astronomically developing countries and have been held in Venezuela, Nigeria, Egypt, Portugal, Yugoslavia, Indonesia, China, and others. Two or three central topics are chosen. For each topic, a suitable faculty member is invited to stay for the entire school. Other topics appear for enrichment and are chosen according to local expertise and availability of other visitors. The IAU provides the prestige of an international venture and seeks to garner local support not only for the ISYA but also for the longer-term increase in local astronomical capabilities. Financial support is provided both locally and by the IAU, when possible ultimately from UNESCO. Perhaps the greatest benefits of an ISYA are the resulting lasting acquaintances and scientific cooperations.