More than ten years passed since the appearance of the first Edition of "Introduction to Zeolite Science and Practice" which book contained the expanded lectures delivered at the Summer School on Zeolites, preceding the 8th International Zeolite Conference (IZC). Over 1600 copies of the 1st Edition found their way to an owner and judging by citation numbers the book is still lively in use. In view of the substantial progress made in the last decade in the fields of zeolites and related materials it was decided to go for an extended 2nd Edition. Unfortunately - as often is the case - this process took more time than expected by the Editors. In the mean time some new texts on zeolites were issued. Thus Weitkamp and Puppe edited the book Catalysis and Zeolites. Fundamentals and Applications (1999). Also in the 5 volumes of the Handbook of Heterogeneous Catalysis (Eds. G. Ertl, H. Kn6zinger, J. Weitkamp, 1997) much information on zeolites, their synthesis and modification, and particularly their use as catalysts can be found.