The long-term purpose of the BEST activity is to improve learning outcomes and necessary skillsof students, particularly the most marginalized groups so that they remain in primary schoolsand effectively transition to lower secondary education. The overarching objective of BEST is tointroduce the most cost-effective education solution to improve Khmer literacy and Read-to-Learn abilities among grade 4 students.Specific objectives are:1) To revise core textbook for Khmer grade 4 and develop cost-effective and practicalliteracy packages for grade 4;2) To improve teachers competencies in teaching literacy in target primary schools; and3) To produce and disseminate evidence that supports the Ministry of Education, Youthand Sports efforts to scale-up successful practices.