What is COM?

Question

I searched hard, but was unable to grasp the whole idea. Can anyone tell me:

• What COM actually is?
• How do GUIDs work, and how are they used by COM? <

Answer 1

10,000 foot view:

COM is the communication mechanism for software components. Example, you can interact with COM interfaces (COM interop in .NET) to use functionality not exposed through a common interface (.NET assembly).

GUIDs are explained fairly decent on Wikipedia http://en.wikipedia.org/wiki/Globally_Unique_Identifier

I always understood LIB files to be object files for the C++ linker. They contain the code for all objects in a cpp file. The compiler optimizes when it links disregarding portions of the object file that it doesn't need.

Someone please clarify as I am sure I butchered some of this.