This book addresses some of the key questions that scientists have been asking themselves for centuries: what is knowledge? What is information? How do we know that we know something? How do we construct meaning from the perceptions of things? And how do we communicate this meaning to others--that is to say, inform them? Although no consensus exists on a common definition of the concepts of information and communication, few can reject the hypothesis that information - whether perceived as an " object " or as a " process " - is a precondition for knowledge. Epistemology can be defined as the study of how we know things in general--this is its primary signification in the anglophone world--or, more specifically, as the study of how scientific knowledge is attained and validated--this is how it is conceived in the francophone world. To adopt an epistemological stance is to commit oneself to render an account of what constitutes knowledge or, in procedural terms, to render an account of when one can claim to know something. An epistemological theory imposes constraints on the interpretation of human cognitive interaction with the world. It goes without saying that different epistemological theories will have more or less restrictive criteria for distinguishing what constitutes knowledge from what is not. If information is a precondition for knowledge acquisition, giving an account of how knowledge is acquired should affect our understanding of information and communication as concepts.