The book dwells on those avian orders that have accumulated selected genetic variations over the geological time scale. It provides an all-embracing view of the hereditary carrier to the readers, taking them to the realm of colorful avian species. The readers would visually comprehend, through lucid explanation and vivid illustrations, in the book, how chromosomal rearrangements, within interbreeding populations of birds, persist and contribute to the process of speciation. It's an exhaustive compilation of 30 years of research, carried out by the author on various species of birds - a treasure trove for readers who are interested in avian cytogenetics. The present book is a practical guide to those curious minds who often seek biology in a simple form where the crux is not hidden in the myriad of complex words, indeed!