The ‘Lilian Voudouri’ Music Library by the Friends of Music Society is the largest music library in Greece. Unique in its kind, it is open to a large spectrum of audiences, such as students, researchers, artists and lovers of music and of the arts. Mathematics and music share a very important bond ever since antiquity. In music, only precise mathematical relationships can emit harmonious sounds. This happy medium was the starting point for our inspiration and it has been used by numerous musicians in their work. It is an identity communicating an institutional body with a modern, structured profile and a center for knowledge and culture, open to all.