  Four-dimensional N=1 supersymmetric gauge theories with two adjoints and a
quartic superpotential are believed, from AdS/CFT duality, to have SL(2,Z)
invariance. In this note we review an old, unpublished argument for this
property, based solely on field theory. The technique involves a complexified
flavor rotation which deforms an N=2 supersymmetric gauge theory with matter to
an N=1 theory, leaving all holomorphic invariants unchanged. We apply this to
the N=1 gauge theory with two massless adjoints and show that it has the same
auxiliary torus as that of N=4 gauge theory, from which SL(2,Z) invariance
follows. In an appendix, we check that our arguments are consistent with
earlier work on the SU(2) case. Our technique is general and applies to many
other N=1 theories.
