Drawing on data from eleven preschools in four European countries (Germany, Belgium, Sweden, and the UK), this edited volume explores the progress of preschool children learning English over a period of two years. In the first volume, children's lexical and grammatical comprehension, the quality of L2 input, the effect of immersion on L1 development, comparisons with English monolingual children, as well as intercultural learning are addressed. In addition, environmental learning in an immersion context, labelled "green immersion," is outlined with reference to a bilingual preschool located within a zoological garden. The following are included in this report: (1) Introduction (Kristin Kersten, Andreas Rohde, Christina Schelletter, & Anja K. Steinlen); (2) The Input Quality Observation Scheme (IQOS): The Nature of L2 Input and its Influence on L2 Development in Bilingual Preschools (Martina Weitz, Svenja Pahl, Anna Flyman Mattsson, Aafke Buyl, & Elke Kalbe); (3) Receptive L2 Lexical Knowledge in Bilingual Preschool Children (Andreas Rohde); (4) Receptive L2 Grammar Knowledge Development in Bilingual Preschools (Anja K. Steinlen, Gisela Håkansson, Alex Housen, & Christina Schelletter); (5) Lexical and Grammatical Comprehension in Monolingual and Bilingual Children (Christina Schelletter & Rachel Ramsey); (6) SETK 3-5: A Developmental Language Test on German for 3-to-5-Year-Old Children (Anja K. Steinlen, Katharina Neils, Thorsten Piske, & Christian Trumpp); (7) Intercultural Encounters in Bilingual Preschools (Lydia Gerlich, Holger Kersten, Kristin Kersten, Ute Massler, &Insa Wippermann); (8) Green Immersion (Shannon Thomas, Petra Burmeister, Michael Ewig, Kristin Kersten, & Suzanne Akerman); (9) Animal-Supported Environmental Education in a German-English Zoo Preschool (Inge A. Strunz & Shannon Thomas); (10) Profiles of the ELIAS Preschools (Insa Wippermann, Christine Tiefenthal, Annelie Schober, & Lena Gotthardt). The ELIAS Preschool Overview Questionnaire (ELIAS POQ) is appended. [For "Bilingual Preschools. Volume 2: Best Practices," see ED572868.]