In the USA, the number of college students with limited English proficiency is increasing. Even after successfully completing a course of English as a second language, many face both linguistic and cultural barriers in mainstream classes. This book focuses on both the theory and practice of assisting such students, especially in the sciences. As the number of non-native English speaking students increases at colleges and universities, innovative approaches are needed to successfully educate this population and how science is taught may be crucial. Instruction in the students' native language may become increasingly important in attracting and retaining non-native English speakers in college. This book is aimed primarily at staff who teach science to LEP undergraduates, but others who should be interested include staff involved with postgraduate students and high school science teachers.