Oh Christ define threadwide, You know how windows can do loads of things at once (Multi-Tasking) the way it does this is by dividing everything up into threads, Ie your VB App is one thread, Word is a different thread, anything else running is a different thread, some programs use several threads but it's damned hard in VB. When you set a hook you need to give it a procedure to run when the hook is called, (ie the procedure you want to process all the keypresses in) If you want to sed a global hook you have to get a different thread to run your code, but it can't get at the memory because that memory is assigned to a different thread. If you wan't to set a global hook you have to make a standard dll which can be run from all threads, which you can't do in VB because they're seen as a bit old fashioned.

NB I've oversimplified this, there's something called a process which is like a container for threads but in VB you can only really have one thread per process so it doesn't matter.