Various improvements have broadened the research in the eld of zeolite membranes and lms, such as the development of new synthesis procedures, the use of new supports with specic characteristics (monoliths, foams, etc.), or the use of modied supports by means of masking or grafting techniques, the application of new analytical techniques (isotopic-transient experiments, permporometry, pulsed eld gradient nuclear magnetic resonance [NMR], interference microscopy, IR microscopy, etc.), the control of the orientation of the crystals (by means of covalent linkages, synthesis conditions, etc.) and of the thickness of the membranes, and the preparation of new zeolites as membranes or new zeoliterelated materials. In addition, a variety of zeolites can now be prepared as colloidal systems with particle dimensions ranging from tens to a few hundred nanometers.