I’m learning about blocks in AC2006.  I created a layer to hold the block (Block),
then selected a component from a different layer (Drawing).  After the block was created I found that the
Drawing layer was now empty.  Is this
normal?  So if I had used drawings from
several layers to create the block, those parts used in the block would vanish
from their respective layers?  Is there
any way to avoid this?

I’m thinking of a situation where I may want to have
several blocks that use some of the same parts, but the parts need to be
modified before each block gets created. 
To lose the original drawing layers makes this difficult.

Any suggestions?

Thank You,
Roger

The Drawing layer is not empty - only the original entity got converted to the block and the block now references the Drawing layer. There is an option in the BLOCK command whether to keep or delete the original/source entity.