Dak Rahasya is a captivating Bengali language mystery novel book that was written by Sukanta Gangopadhyay. Here I have added a free PDF copy of this book and going to share it freely with you. The writer of this novel Sukanta Gangopadhyay was an eminent Indian Bengali writer who was born in 1961 in Hugli, India. He has a lot of fascinating work among them the Dak Rahasya is one. The last edition of this book was published by Ananda Publishers in 2015. Enjoy this book from here.