[Tutor] Puzzled by execfile()

[André Roberge]

Dear Tutors,

I have the following two Python files

===Script1.py ===
def printfoo():
    print "foo"
execfile("Script2.py")

===Script2.py===
from Script1 import *
print "starting"
printfoo()
print "done"
==============

When I run Script1 for the FIRST time (from within IDLE or PythonWin), I get

starting
foo
done
starting
foo
done

When I run it again, I only get

starting
foo
done

each time that I run it.  I don't understand why Script2 seems to be run 
twice the first time around

André Roberge