uses Mapi;
...

procedure TfrmMain.btnOpenAddressBookClick(Sender: TObject);
var
  lhSession, rc: Cardinal;
  lpnNewRecips: PULONG;
  lppNewRecips: PMapiRecipDesc;
  lpRecips: MapiRecipDesc;
begin
  lpnNewRecips := nil;
  rc := MAPILogon(0, 'Севостьянов Игорь', '', MAPI_LOGON_UI, 0, @lhSession);
  if (rc < > SUCCESS_SUCCESS) then
    SysErrorMessage(rc);
  rc := MAPIAddress(lhSession, 0, 'Адресная книга', 0, '', 0, lpRecips, 0, 0,
    lpnNewRecips, lppNewRecips);
  if (rc < > SUCCESS_SUCCESS) then
    SysErrorMessage(rc)
  else
    rc := MAPIFreeBuffer(lppNewRecips); // free the memory used by MAPIAddress
  if (rc < > SUCCESS_SUCCESS) then
    SysErrorMessage(rc);
  rc := MAPILogoff(lhSession, 0, 0, 0);
  if (rc < > SUCCESS_SUCCESS) then
    SysErrorMessage(rc);
end;