I have a workbook w/three different worksheets. They all contain a column
that has employee IDs each with the same heading. So the columns match, they
just contain different #s.

I want to pull the ID #s from all three worksheets into a fourth "master"
worksheet that will update when new numbers are added to the sheets. (EX:
Sheet1- employees who attended training in Boston, Sheet2 = New York, Sheet3
= London. I want Sheet 4 = list all ID#s from all of the cities. When I add
new ID#s to Sheet 1, 2, or 3, Sheet 4 will update to reflect the new ID#s).

Is that possible?