When an application is told to close due to impending Windows shutdown, is
there a way for the application to determine that this is the reason for
shutdown, as opposed to someone clicking on the close icon on the form's
title bar?

Trap the WM_QUERYENDSESSION message that windows sends before
shutdown. Look for it in win32.hlp.

I am using this to put my program in the registry so it automatically opens again when windows is restarted.
(Sorry for swedish comments!)

//========= Detta k?rs om windows st?nger programmet. (Endast fria) ===================//
procedure tmditted.WMEndSession (var msg : TWMEndSession);
var
  reg : tregistry; //F?r att kunna komma ?t registret
begin
  reg := tregistry.create; //Skapa en koppling till registret
  try
    reg.rootkey := HKEY_CURRENT_USER; //V?lj grundnyckel
    if reg.openkey ('\Software\Microsoft\Windows\CurrentVersion\Runonce',true) then //Om det g?r att ?ppna denna
       reg.writestring ('TTSGMLED','"'+paramstr(0)+'"'); //S? skriv in ttsgmled
       //Detta g?r att ttsgmled startas automatiskt n?r man startar om windows
  finally
    reg.closekey;   //St?ng nyckeln
    reg.free; //Frig?r registerkopplingen
    inherited; //K?r resten av de inbyggda rutinerna
  end;
end; //WMEndSession

johan