Marching Cubes is an algorithm for the construction of surfaces. In the context of scientific visualisation, most commonly this is an isosurface, and Marching Cubes lends itself to this application very well. The surfaces are considered to be infinitely thin and reasonably well behaved -- as shown in Section 3.4 Marching Cubes often has problems with surfaces that misbehave.
Marching Cubes is a high resolution method which derives from similar work on contouring. It requires node based volumetric data.