Yes, you can copy and paste an entire workbook into another one. This will preserve all the formulas and connections between sheets. Here are the steps to do this:

1. Open both workbooks in Excel.
2. In the source workbook, right-click on the sheet tab of the first worksheet you want to copy and select "Move or Copy".
3. In the "Move or Copy" dialog box, select the destination workbook from the "To book" dropdown menu.
4. Check the box next to "Create a copy" and click "OK".
5. Repeat steps 2-4 for all the worksheets you want to copy.
6. Once you have copied all the worksheets, save the destination workbook.

Alternatively, you can also copy and paste the entire workbook by following these steps:

1. Open the source workbook and click on the "File" tab.
2. Select "Save As" and choose a location to save the copy of the workbook.
3. In the "Save As" dialog box, select "Excel Workbook" from the "Save as type" dropdown menu.
4. Give the copy of the workbook a new name and click "Save".
5. Open the destination workbook and click on the "File" tab.
6. Select "Open" and navigate to the location where you saved the copy of the source workbook.
7. Select the copy of the source workbook and click "Open".
8. The entire workbook will now be copied into the destination workbook.