P.N. Natarajan is former Professor and Head, Department of Mathematics, Ramakrishna Mission Vivekananda College, Chennai. He did his Ph.D. from the University of Madras, under Prof. M.S. Rangachari, Former Director and Head, The Ramanujan Institute for Advanced Study in Mathematics, University of Madras. An active researcher, Prof. Natarajan has over 100 research papers to his credit published in International Journals like Proceedings of the American Mathematical Society, Bulletin of the London Mathematical Society, Indagationes Mathematicae, Annales Mathematiques Blaise Pascal and Commentationes Mathematicae. He has so far written 4 books and contributed a chapter each to two edited volumes, published by the famous International publishers Springer, Taylor-Francis and Wiley. His research interest includes Summability Theory and Functional Analysis, both Classical and Ultrametric. Prof. Natarajan was honoured with the Dr. Radhakrishnan Award for the Best Teacher in Mathematics for the 1990-1991 by the Government of Tamil Nadu. Besides visiting several institutes of repute in Canada, France, Holland and Greece on invitation, Prof. Natarajan has participated in several International Conferences and has chaired sessions.