Examined peer-reviewed research on the Transtheoretical Model (TTM) and tobacco cessation and prevention. Results found growing evidence for the TTM's validity as applied to tobacco use, though the evidence was inconclusive. Eight different staging mechanisms were identified, raising the question of which are most valid and reliable. Interventions tailored to a smoker's stage were more successful than non-tailored interventions in promoting forward stage movement. (Contains tables and references.) (SM)