This work seeks to establish possible synthesis challenges in the zeolitic material field over the coming years. The choice may be subjective but it is worth reflecting on such an important question. The most pressing synthesis challenges in the opinion of the authors described in the following pages are: (1) elucidation of the nucleation and growth mechanism of zeolites; (2) controlling zeolite crystal size and growth habit; (3) preparation of extra-large pore zeolites; (4) synthesis of zeolitized mesoporous materials; (5) synthesis of chiral zeolites; (6) preparation and modification of layered zeolites; (7) and preparation of true molecular sieve membranes. (C) 2009 Elsevier B.V. All rights reserved.