Once upon a time there was a curious man. He knew nothing about the subject called “Information Technology.” One day he visited a library and suddenly saw a book entitled “Information Technology: The Art of Managing Information.” First, he thought: “This title is not for me. Let me ignore it and look at the next title.” But then the curious man started thinking: “What is it? What is information technology? What is information? Why do I need to know how to manage it?” Since a curious man lives in all of us, it would be tempting to follow the sequence of his thoughts and try to answer these questions. Let us start with a simple question: What is information technology? This question is very important as far as this book or any other text related to information theory is concerned. The simplest answer to this question is already provided in the title of that book as: Information technology is the art of managing information. As soon as we accept this particular deﬁnition, the other two questions that appeared in his mind become extremely relevant. In this chapter, we will try to answer those two questions and develop a quantitative perception of classical and quantum information. Once a basic perception is built in the ﬁrst part of this chapter, we will describe a short history of quantum computation and quantum communication at the end of this chapter.