This issue of Catalysis Today presents a selection of contributions to the 11th International Symposium on the Scientific Bases for the Preparation of Heterogeneous Catalysts (PREPA11), held on the campus of the “Université catholique de Louvain†(UCL) in Louvain- la-Neuve, Belgium, on July 6–10,2014. This series of symposia was initiated in 1975 on a regular 4-year interval basis. Previous proceedings of these symposia have been published in Studies in Surface Science and Catalysis. As for previous editions, this 11th symposium was made possible thanks to the organizational skills of the members of the research groups active in heterogeneous catalysis of the “Institute of Condensed Matter and Nanosciences†of the UCL and the “Centre for Surface Chemistry and Catalysis†of the University of Leuven, KU Leuven, Belgium. Only the oral communications and some selected posters were invited to contribute to the present publication. The submitted full manuscripts then followed a systematic and strict peer-reviewing procedure carried out by recognized experts in the field. In order to maintain a high scientific level,3 referees, and sometimes more, were invited to evaluate the manuscripts. In the end, the issue gathers 28 contributions.