The book, A Defining Tool of Anthropology is a small effort by me in the field of physical anthropology. This e-book has been written in the easiest possible language, so that it could be understood and associated with anyone and everyone, who is new to this subject. The e- book gives us a brief insight about anthropology, while focusing on anthropometry, its branches, historical perspective, its applied approach and instruments that are mostly used in anthropometry, while taking measurements. The book comes handy for those who desire to understand the basics of anthropometry, especially the under graduates of this field.