Adobe Acrobat 7 Professional - Manual (Page 483)

Combining Adobe PDF documents
You can use the Insert command to append or insert an Adobe PDF document into another
PDF document.You can also insert one or more documents into a PDF document using
drag and drop.
To combine files using the Create PDF From Multiple Files command, see Creating
Adobe PDF files from multiple files .
To combine two Adobe PDF documents using the Insert Pages command:
1. With the target document open, choose Document > Insert Pages.
2. In the Select File To Insert dialog box, select the source document you want to insert into
the target document, and click Select.
3. In the Insert Pages dialog box, specify where you want to insert the document, and
click OK.