When I wanted to link Visual Leak Detector, I did something magical and whenever I want to #include it, I can do so in any project without doing anything else.
With the boost library, I have to link it to every project individually before I can use it. In the C/C++ settings, the directory to the Visual Leak Detector library is *always* in the "Additional Include Directories". And when I go in to add the Boost library in that same place, the Visual Leak detector library is placed under "inherited values" while adding the Boost library only adds it to "Evaluated Value":
You have to add the Boost directory to the default header search paths. This used to be much easier in earlier versions because it was in a reasonable location. Nowadays:
First you need to load any C++ project or solution. Then open the property manager (View > Property Manager), and you'll see a window listing every C++ project in the solution. Expand any of them and you'll see a folder for each build configuration. Open one and one of the items will be "Microsoft.Cpp.<architecture>.user". Right-click > Properties > Common properties > VC++ Directories > Include directories is where you add new directories. You have to do this for both x86 and x86-64. Note that although it looks like you're setting something just for that one project, the setting is actually compiler-wide.
You'll also need to add the library location. Although Boost will automatically link to the correct .lib, the compiler still needs to know where to look for them.
I am glad you asked the question since I have been wondering how, if at all, to make 3rd party library headers and library files be automatically included when using them. I would never have thought to go looking for the property manager.