>If AProc is running the private exists. I have no idea how you can see memory for the calling procedure while Aproc is still running. If Aproc is running then the calling procedure is not running

Right, but the moment you declare a PUBLIC, you can see it above (using the Locals window) while Aproc is running, where PRIVATE is just how you described, you can't see it there, that is a difference ...

>VFP is single threaded. When aproc is finsihed and control returns to teh calling procedure the private variable will no longer exist.

... that may or may not make a difference because of this fact. The only place this would really make sense is in DynamicProperties (of say a grid, and hopefully controls in the future) but this still doesn't make sense because before this happens the property wouldn't be valid.

The point is, using the Locals window, you can see the differences between the two. This is how it works, if there is any relevance to that fact, I don't know.