The study of human adaptation to high altitude has been an interesting area of research in physical anthropology, physiology, as well as in medical sciences. The question on 'how human adapt to high altitude environments?' receives considerable attention from researchers because of the distinctive characteristics of high altitude environment. This book is a brief presentation of a comparative-quantitative research which was carried out among the Monpas of West Kameng and Tawang districts in Arunachal Pradesh from September 2012 to August 2015 with an objective to understand the adaptation pattern of the Monpas vis-à-vis other high altitude (e.g., Andean and Tibetan) populations. It focuses on the analyses of those variables that by and large fall within the field of physiological anthropology (Physiological, and Hematological characteristics); other traits i.e., skin fold thickness, body fat (fat%, fat-mass, fat-free mass), and BMI are also selected for the purpose of analysis. The author invites the readers to be generous in their critical appreciation, forgiving the limitations they might find in some places, but exploring the insightful findings this book presents.