The Soviet Union collapsed more than 20 years ago, but the traces left in occupied countries by this monstrous system still affect the lives of millions of people. Under the glittering surface of newsworthy events that regularly appear in the mass media, there are many other wounds hard to heal. The system of education is one of the social structures that was fundamentally affected by Soviet power. Due to unique historical, demographic, and cultural reasons, the experiences of other countries providing education to non-native speaking students cannot be adopted in Estonia without first studying the situation thoroughly. The Estonian Ministry of Education and Research launched the longitudinal study "Non-Estonian Child in an Estonian-Language School", with the aim to understand how Estonian schools cope with an increasing number of non-Estonians studying in a second language. This book brings together some results of that study. This book contains the following: (1) Why this study? A view from the Estonian ministry of education and research (Maie Soll); (2) Bilingual and monolingual students' linguistic competences and their development at Estonian primary school (Krista Uibu and Kristiina Tropp); (3) Cognitive abilities and math achievement of students from Estonian-, Estonian-Russian-, and Russian-speaking families in Estonian-language classrooms (Eve Kikas); (4) Longitudinal explorative study of mono- and bilingual pupils' differences in math achievement: the role of Estonian and Russian instructional environment (Kristina Seepter); (5) Errors in solving arithmetic word problems. Differences between students from Estonian- and Russian-language schools (Anu Palu, Reelika Suviste, and Eve Kikas); (6) Teachers' judgments of monolingual and bilingual students' reading skills: child-, class-, and teacher-related factors (Piret Soodla); (7) Relations between mono- and bilingual pupils' math achievement and teachers' knowledge of special education needs (Kristina Seepter); (8) Bilingual student well-being in submersion education: changes in self-esteem and school satisfaction during the fourth grade (Aivar Ots and Margit Tago); (9) Development of self-reflection ability and its relations to scientific concept thinking in mono- and bilingual children: are bilinguals doing better? (Grete Arro); (10) Ethnic stereotyped attitudes in relation to social relationships in fourth grade students (Hanna Reek); and (11) Children studying in a wrong language: looking for ways to improve (Aaro Toomela).