The term supplementary education is used internationally to refer to various forms of out of hours learning. This includes a creative, diverse, and underresearched sector that encompasses fragile, low-cost schools, organized by minority ethnic communities in urban areas, to teach their children about their heritage. The term is also used to refer to the rapidly expanding individual and school-based tutoring services established as businesses, and known in east Asia as cram schools or shadow education, set up specifically for exam preparation (approximately 80% of children attend such schools in South Korea). The type of supplementary education explored in this entry is the alternative, less formal educational provision, which is broadly organized around four core areas: (1) academic attainment, (2) language teaching, (3) heritage and culture, ...