Exhibit
4
The
undersigned, Charles E. Harris and Susan T. Harris, hereby agree to file jointly
this 13D and all amendments, with respect to the Common Stock of Harris &
Harris Group, Inc., but disclaim that they are a group.
Date:
February 6, 2008
/s/
Charles E. Harris
Charles
E. Harris
/s/
Susan T. Harris
Susan
T.
Harris