For nearly 30 years, it has been known that methanol may be converted to a mixture of hydrocarbons and water over protonated zeolites. During this time, a large amount of work has been carried out to obtain an understanding of the reaction mechanism involved [C.D. Chang, Catal. Rev. 25 (1983) 1; M. Stoeker, Micropor. Mesopor. Mater. 29 (1999) 3; C.D. Chang, Shape-selective catalysis: chemicals synthesis and hydrocarbon processing, in: C. Song, J.M. Garces, Y. Sugi, (Eds.), ACS Symposium Series, vol. 738, Washington, DC, 2000; J.F. Haw, Phys. Chem. Chem. Phys. 4 (2002) 5431; J.F. Haw, W. Song, D.M. Marcus, J.B. Nicholas, Acc. Chem. Res. 36 (5) (2003) 317]. We here aim at presenting some major contributions to today's rather unified view on the MTH reaction mechanism, and, based on this detailed knowledge, to point at possible options for optimizing the performance of MTH catalysts. (c) 2005 Elsevier B.V. All rights reserved.