This issue of Catalysis Today presents a selection of contributions to the 12th International Symposium on the Scientific Bases for the Preparation of Heterogeneous Catalysts (PREPA12), that was held on the campus of the “Université catholique de Louvainâ€(UCLouvain)in Louvain-la-Neuve,Belgium, on July 8–12, 2018. This series of symposia was initiated in 1975 and occurred on a regular 4-year interval basis. As for previous events, this 12th Symposium was made possible thanks to the organizational skills of the members of the research groups active in heterogeneous catalysis at the “Institute of Condensed Matter and Nanosciences†of UCLouvain, Belgium, and of the “Centre for Surface Chemistry and Catalysisâ€of KU Leuven,Belgium. A specificity of this series of symposia has always been a balanced participation of delegates from industry and academic spheres. As for the previous editions, the 12th edition of the Symposium provided an efficient platform for exchanges between these two worlds. The topics covered by the symposium can be listed as: the design of new catalytic materials, shaping and upscaling and reactor design, bi-metallic nanoparticles and mixed oxides,heterogeneization and study of active phase/support interfaces, zeolitic materials and alumina-based materials, new preparation methods for heterogeneous catalysts, electron microscopy characterization for synthetic problems.