Historical and regional collections as well as private libraries of famous people play an important role in raising awareness of our national library treasure and cultural heritage. Legacy is legularly a rich source of information on social history of a city, region or wider area. In this sense we aslo view the presentation of a private library of the Osijek and Croatian translator, journalist and philosopher Viktor D. Sonnenfeld. Reconstruction of a private library of that kind and the selection of material about it are of great help to the research of cultural and historical circumstances in wich the collector lived, they reflect the spirit of the former owner, bibliophile, reader and the spirit of the time in wich this library emerged. This paper deals with the Sonnenfeld legacy on informational level of the collection and techniques focusing on the collection. On the basis of the most important collected data on units of library material in the legacy and holdings content analysis the collection has been estimated according to its size, area, importance and informational value. Since Viktor D. Sonnenfeld was a representative of the Osijek 20th century intellectauls, and based on the content analysis and analysis of his person as a reader, collector and owner of a private library, the paper contributes to drawing conclusions on informational, educational and cultural relationships and needs of Croatian intellectual circles in the early and mid 20th century. The selection of books in the legacy witnesses of Sonnenfeld's strong connection to German culture. He followed the trends and tried to introduce them in Osijek in his everyday life (speech and notes on books in German) and work (translation activities, publishing and journalism) but the very fact that his private collection was posthumously donated to the local library spekas in favour of the benefit of promoting German-Croatian ideas in the local community. For the purpose of more qualitative legacy management the aim of the research has been legacy structure, legacy information content and its features. The aim was also to establish a more qualitative legacy management model since legacy makes a special sort of collection in libraries so as to make the model applicable in future similar legacy collections. The Sonnenfeld legacy processing, organisation, protection and presentation are necessary in sense of holdings preservation as a part of cultural and social identity and heritage. Thus, the library as a factor of cultural, social and scientific development plays a great role here. Legacy has a paricular value (educational, scientific, regional, artistic, ethnographic etc.) and can serve as a testimony of the time and space in which it emerget both for the institution in which it is kept, the city and the region. Quantitative analysis of the Viktor D. Sonnenfeld legacy raises many questions and in necessary for any further research and further quantitative collection analysis. Special contribution of the Viktor D. Sonnenfeld legacy lies in scientific, research and educational needs as well as in historical and cultural heritage of Osijek, Slavonia and Croatia. The legacy Sonnenfeld collection is a small contribution to the history of private libraries in Osijek, Slavonia and Croatia.