How can I determine the person who is currently working in the spreadsheet

How can I determine the person who is currently working in the spreadsheet

I'd like to generate a "Last Change when/who" entry in a spreadsheet. I was successful with time/date but I have no clues how to find out who is the person who was doing the change.

  1. Private Sub Worksheet_Change(ByVal Target As Range)
  2. Application.EnableEvents = false
  3. On Error Goto ENEV
  4. range("LastChangeDateTime").Value=Now ' <- this works perfect
  5. range("LastChangePerson").Value=???? ' <- what should I enter here?
  6. ENEV:
  7. Application.EnableEvents = true
  8. End Sub