It seems to me over a period of thirty years I have been engaged in degree course teaching services under the University of Calcutta. I still remain to be an under developer of knowledge or rather an illiterate to write this book. Sri Sri Ramkrishna Kathaamrita bestowed on me by generating ideas to write something for the human being on the earth. Ramkrishna kathaamrita teaches me to think and incubate the ideas and those ideas are essential sources of knowledge that has been contained in this book. I have tried a little to accumulate all ideas through my publications in papers. Those ideas...