Revolution and Reform

Here's Raymond Geuss (from his generally excellent "Dialectics and the Revolutionary Impulse" from the Cambridge Companion to Critical Theory) on the distinction:

"First, reform is distinguished from revolution in that a reform is construed as a change in relatively superficial rather than very basic structural features of society. Second, a reform is thought to be a process of gradual transformation in contrast to abrupt revolutionary change. Finally, a reform is a transformation carried out by mobilization of forces not merely endogenous to the given political system, but recognized by it, that is, with an acknowledged place in it, whereas a revolution often, or even usually, depends on the action of forces that are in some sense not recognized as legitimate."