The most common use for maps is to improve the appearance and realism of Materials. You can also use maps to create environments or projections from lights (see Advanced Effects Rollout ).
Maps can simulate textures, applied designs, reflections, refractions, and other effects. Used with materials, maps add details without adding complexity to the geometry of an object (an exception is the Displacement mapping, which can modify geometry.)
With the mental ray renderer, a shader can be the equivalent of a map. You assign a shader to a material in the same way you assign a map.
Accessing Map Types
You use the Material/Map Browser to load a map or create a map of a particular type. In the Slate Material Editor, by default the Browser is a panel that is always visible. In the Compact Material editor, the Browser opens when you click a map button, 
(Get Material), or the Type button while the editor is at a map level.
How to Remove a Map
To remove a map from a material, use the Slate Material Editor. In the active View, you can disconnect the wire, delete the wire, or delete the map itself. See To remove a map or map connection.
Maps and mental ray Shaders
When a mental ray renderer is active, the Material/Map Browser also lists mental ray shaders. Shaders are similar to maps, and you assign them the way you do maps. See mental ray Shaders for links to shader descriptions.
mental ray maps in the Browser list
Show Incompatible. Maps and Mapping Coordinates
Maps have a spatial orientation. When you apply a material with maps in it to an object, the object must have mapping coordinates. These are specified in terms of UVW axes local to the object.
Most objects have a Generate Mapping Coordinates toggle. You can turn this on to provide default mapping coordinates. If the object has this toggle, it is also turned on automatically when you render the scene, or use Show Map In Viewport.
Some objects, such as editable meshes, don't have automatic mapping coordinates. For these types of objects, you can assign coordinates by applying a UVW Map modifier. If you assign a map that uses a mapping channel, but don't apply a UVW Map modifier to the object, the renderer displays a warning that lists objects that require mapping coordinates. You can also use UVW Map to change an object's default mapping.
UVW Mapping Coordinate Channels
Each object can have from 1 to 99 UVWmapping coordinate channels. The default mapping (from the Generate Mapping Coordinates toggle) is always UVW 1. The UVW Map modifier can send coordinates to any of these channels.
Each map in a material can use any UVW channel (if present), or other type of mapping that depends on whether the map is 2D or 3D.
You can set the mapping channel used by NURBS surface sub-objects in their creation or modification parameters.
Mapping for 2D Maps
You can position a 2D map on the surface of an object by using a map channel, any assigned vertex color, or the local or world coordinate systems. You can also choose different environment mappings. See Coordinates Rollout (2D).
Mapping for 3D Maps
You can position a 3D map within the volume of an object by using a map channel, any assigned vertex color, or the local or world coordinate systems. See Coordinates Rollout (3D).
Noise for Maps
Random noise values increase the complexity of maps and can give them a more natural look. For 2D maps, see Noise Rollout (2D). For 3D maps, you can assign a separate Noise map. See Noise Map.