Tamil Nadu have an ancient history. But this history has not been fully revealed. Lack of evidences, unauthorised source materials where the setback for that. But K.K.Pillai’s “History of Tamil Nadu People and Culture” book has been considered as a valuable and authentic work in Tamil Nadu history. This book follows scientific method of research writings. In this book K.K. Pillai try to give full history of Tamil people from pre historic period to modern times. It also proved that Tamil people have an ancient glory and heritage. The author also rejected some false ideas about Tamils past. K.K. Pillai’s this work prevailed as an authentic and reliable work in the history of Tamil Nadu.