Mathematics is a language. To learn and be competent in a language, it is necessary to learn the vocabulary of the language. One should be familiar with the terms, signs, definitions, symbols of Mathematics to get the conceptual knowledge of the subject. This book is designed in order to facilitate the students and learners of Mathematics so as to make a strong hold over the vocabulary of Mathematical Language and provides a quick insight of Famous Mathematicians, their contributions (Theorems and Corollaries) in Alphabetic order (D-H). Also, the book touches each and every branch of Mathematics however, it is from Pure or Applied Mathematics.