S R Ranganathan stays put in our thoughts and work even nearly half a century after his death. Some of his work is classic with lofty ideas which always engender new thoughts for the present age. Ranganathan brought a paradigm shift in theory and practice of library classification, and extended its reach much beyond the library walls. Facet analysis is the order of the day, not only in library classification but also in organizing and searching the web. Now the world is experiencing a second Golden Age of Classification and Indexing in the World Wide Web environment. In fact faceted classification prophesized as the basis of all knowledge organization systems and tools in mid 1950s is proving visibly true today. Classification has bounced back with a vengeance. Late Eugene Garfield aptly said, ‘Ranganathan is to library science what Einstein is to physics’. This work presents a brief summary and importance of Ranganathan’s work in classification, though by no means his best. It is difficult to come out with the best of a treasure in an ocean. He left a huge body of classification literature, full of thought provoking with multidimensional applications. Apart from the Classification Research Group (CRG) disciples his work has inspired many a genius in our profession. True tributes to his importance have been offered from time to time by the greats of our profession. Apart from a summary and chronology of his classification work, this book portrays the current scene on classification studies, practices and literature in India. Lastly it makes a hearty plea to know, value, preserve and perpetuate his legacy bequeathed on us —a legacy which has brought glory to the Indian LIS profession. In nutshell the book is a reminder of his greatness, relevance and our enduring debt to him.