Which program in Visual Studio lets me look into DLLs to see its API?

This is exactly what the Object Browser is for.

  • Add a reference to the DLL.
  • Right click it in the list.
  • Click View in Object Browser.

For those coming from the old Visual Studio 6.0 days:

Dependency Walker is a nice free tool, that was formerly part of Visual Studio.

http://www.dependencywalker.com/

I like it still. Here is a screen shot:

enter image description here