The subject of this research paper is the library both as a public institution and as an architectural structure in the context of contemporary culture. The study traces the role of the library back to the beginnings of human civilization in order to make evident its functional necessity during all times and the changes it has undergone for keeping up with the particular social and cultural circumstances of every period. Thus the endurance and continuous development of the institution is documented based on the constant human need to both enhance and share knowledge as a highly valued public good. Libraries of various kinds (e.g., national, public, university-based, etc.) are studied and analyzed as architectural structures which provide the conditions for the macrocosm of immaterial knowledge to be accommodated in the material realm of an architectural structure with its various design, formal, functional, environmental, and other requirements. A special emphasis is paid to the ways in which a library structure meets the human standards for bodily and perceptual convenience, orientation, and easy access to the resources so that the way to knowledge becomes both an interesting and an enjoyable experience. In the age of digital technology the library is facing the challenge of properly redefining its role as a facilitator to global information accessing. As an enduring “temple of knowledge” the library today, instead of being diminished, or even effaced, by the new means of technology, develops new ways to incorporate them in its mechanism, while at the same time it continues to safeguard quality standards and engage its users in a collective pursuit of knowledge. Through an extensive series of worldwide examples this paper scrutinizes the alternative ways that contemporary architects use in their new library designs for meeting this challenge and for creating small urban paradises in which the material will always meet the immaterial.