This book is about how ESL who are high achievers in mathematics learn mathematics despite their assumed low proficiency in English language, the language of teaching and learning in their country. The six learners were studied in their natural setting to understand how they overcome the barrier of English language when learning mathematics. Higher institutions of learning in their country discriminate selection by attainment in English language in their school leaving examiation. This discrimination criterion was viewed in this study as based on an assumed strong positive correlation between achievement in mathematics and English language, and that learners with limited proficiency in English languange would not cope in mathematics related fields. It was discoverd that English language had a low correlation with mathematics and that these learners had developed high proficiency in the language of mathematics, which aided their understanding of mathematical concepts. Futhermore, they had a positive disposition towards mathematics and a strong inclination towards learning.