For starters I'm using Visual C++ 2008 Express Edition.

That aside, I have a visual studio solution test_project within a directory called test_project. IOW my directory structure is akin to:

c:\code\test_project
test_project.sln
test_project.vcproj
test_project.ncb
main.cpp
- executive
executive.h
executive.cpp
- common
common_header.h

Where within the directory test project there's two directories: "common and executive". Within the common directory there's a file named: "common_header.h". Within the executive directory I have two files: executive.h and executive.cpp

I added an environment variable to my system called: "TEST" with the directory: c:\code
Within my visual studio project I added the following line to my "VC++ Directories".
$(TEST)\test_project\common

From the Project Menu I selected Show All Files which imported the folders common and executive. I then right clicked and added each file within the folders

Later I ammended main to reflect
Code:
 # include "common\common_header.h"
 # include "executive\executive.h"
  int main() {

  }
At issue: I'd like to eliminate the need to specify the directory within the source files. i.e I want to do: # include "common_header.h" as opposed to "# include "common\common_header.h". Trouble is the former generates a compiler error:
fatal error C1083: Cannot open include file: "common_header.h".

How do I circumvent this?