How to transfer layers and blocks from one drawing to another?

Starting with AutoCAD 2000 you can use the AutoCAD DesignCenter function to do this transfer (copy). But you can also use a simpler method.

Open the target drawing, start the Insert command and pick the (source) DWG drawing containing the layers and blocks you want to transfer. When prompted for an insertion point, press [Esc]. The graphics of the drawing will not be inserted, but the target drawing now contains the layers and blocks from the inserted drawing file.