The RHIC Spin Collaboration[15,16] (RSC), a group of experimentalists, theorists, and
accelerator physicists, was formed in 1991 with the objective of advancing the case for a
polarized collider program at RHIC. The RSC proposal update containing sections on,
(A) polarized collider operation of RHIC, (B) the PHENIX detector spin physics program,
and (C) the STAR detector spin physics program, was approved by the PAC in October 1993.
The cost estimated for instrumenting RHIC to provide polarized-beam capability is 
$10M.
During the past year the RIKEN Spin Group (RSG) has undertaken an initiative
to provide a large part of the polarized collider equipment. In addition, the
RSG will fund a major upgrade of the PHENIX muon spectrometer, making
feasible for the first time an extensive program of high-
measurements
of single-muon and dimuon production. The present proposal, authored by an
enlarged collaboration, PHENIX/Spin, addresses the physics program to
be carried out with the upgraded PHENIX detector. The physics program
described in the PHENIX subsection of the RSC proposal covered measurements
feasible with the
Conceptual Design Report (CDR)[25]
version of PHENIX, including
inclusive direct photon production and 
production via electron
detection. As the case has already been made for this suite of measurements,
the present proposal focuses only on new capabilities.