With an introduction explaining how contemporary developments in the fields of genetics, statistics and probability theory blended to evolve the subject of quantitative genetics, the book deliberates on how genetic theory is built on measured trait values (phenotypes) leading further to analysis of genetic variation encompassing several areas like genetic divergence, inbreeding, heterosis, mating systems, mating designs and theory of selection. Presentation of established concepts in a new light, a fresh look at QT basics with a special attention to traits governed by two genes, and a new orientation to genetic divergence and various genetic parameters in random mating and inbreeding populations are new highlights. The engaging presentation is expected to motivate even those with little mathematical/statistical background, and those professing diverse fields like agriculture, biology and biotechnology for quality experimentation. Written by a well-known author associated with the School of Quantitative Genetics at the Indian Agricultural Research Institute, New Delhi, for more than three decades, the book is founded on the author’s vast experience in inventive research, motivated teaching and guidance to graduate students. A clear and comprehensive account of vital topics in Quantitative Genetics like Distributions, Genetic Analysis of Phenotypic Variation, Genetic Values, Genetic Effects and Variances, Inbreeding and Heterosis, Genetic Divergence, Mating Systems, Selection and Populations is given in an easy-to-understand style substantiated by practical examples. Efforts have been made to keep the book short, which augments the learning experience of the students and makes it interesting for enthusiasts. It is meant to be an essential companion to students, researchers, teachers and professionals for quality experimentation in genetics and plant breeding.