In Excel, you can quickly copy an entire worksheet from one workbook to another workbook. This allows you to import data from other workbooks with ease and without having to copy/paste everything between the worksheets.
This is a much better way of importing data between workbooks in Excel than just selecting all of the data and copy/pasting. With the method above, you are assured of importing all of the data from the worksheet and having it look exactly the same, all the while only taking a few seconds.
Make sure you check the Create a copy check box so that you will not remove the worksheet from the source workbook. This is an easy mistake to make and you might not notice it for a while.
Download the accompanying workbooks so you can test out this feature of Excel.