Sources of knowledge are provided to people through many social institutions. A fundamental social institution that provides information and supports knowledge is a library. During the past few year in the city of Lamia takes place a development that concerns the creation of an Institution of Higher Education as well as a future creation of more. The existing library of Lamia does not suffice and cannot cover the needs of today’s rapid growth. Therefore, there is an imperative need for the creation of a new library. The composition is based on the idea of the reconstruction of the hill in its initial form before the construction of the hospital that exists there now and will be transported. The building, therefore, is developed inside the hill as a part of it and its landscape. The main axis of the building is the axis of the entry that conceivably connects the hospital with the city. Paralleled with this axis are developed the rest of the main axes of the building that includes the following elements: a vertical volume to these axes, one central atrium to which are directed all the facades of the building and another atrium that contributes to the distinction of the most basic volume of the building, which distinguishes from it, includes the main volume of its reading rooms and helps the building to be seen by the people that comes by. Also, in the atrium, there is an observatory that connects all the elements of the project to the mountain and to the city. Finally, the large spaces of glass and the formation of the atrium with all kinds of materials and with surfaces of water contribute to the completion of the building. At the same time, the fact that it is an underground building contributes to the saving of energy, because of the great thermal mass of the ground. The library includes several departments such as: the department of the historical triangle, a department of magazines, an isolated department, a department with computers, a department that includes historical files and the administration of the whole building. All the departments of the library along with the administration and the way that the building is structured are composed so that it functions properly, it serves its users and it attracts new ones.