Norman Irvine wrote:
I have a light and switch at the bottom of the stairs and a switch at
the top floor. I would like to add a 2nd light at the top of the
stairs above the present switch to illuminate the upper stairs.

Hopefully I can tap into the existing switch.
Is this possible with no extensive rewiring of the system ???

Thanx for any replies

You'll have to tap into the light, not the switch.