The Proceedings of the 24th International Solvay Conference on Chemistry comprise contributed short personal statements and transcripts of in-depth discussions on "Catalysis in Chemistry and Biology" from a by-invitation-only select group of 48 eminent scientists, including four Nobel Laureates, from all parts of the world. The theme of the conference was presented in six sessions, along which the Proceedings are organized. The first session on "Homogeneous Catalysis," chaired by Professor Robert Grubbs, is devoted to basic research on catalysis in homogeneous solutions and applications thereof. "Heterogeneous Catalysis and Characterization of Catalyst Surfaces," chaired by Professor Gerhard Ertl, includes extensive references to industrial applications of catalysis on solid supports, and discussions on the experimental techniques used in this field. "Catalysis by Microporous Materials," chaired by Professor Mark E. Davis, is devoted to a detailed characterization of this particular class of solid support catalysts, with special emphasis on model analysis of the processes catalyzed by these materials. "Catalysis under Extreme Conditions: Studies at High Pressure and High Temperatures — Relations with Processes in Nature," chaired by Professor Henk N W Lekkerkerker, broadens the scope of the two preceding sessions with exciting illustrations. The sessions on "Catalysis by Protein Enzymes," chaired by Prof. JoAnne Stubbe, and "Catalysis by Ribozymes in Molecular Machines," chaired by Prof. David Lilley, present at the same time an exciting extension of and a contrast to the initial four sessions. The combination of the six sessions provides an impressive overview, giving innovative insights into relationships between catalysis in chemical processes and in biological systems, and a unique outlook to anticipated developments in the coming years and the more distant future.