  We construct the nuclear and quark matter equations of state at zero
temperature in an effective quark theory (the Nambu-Jona-Lasinio model), and
discuss the phase transition between them. The nuclear matter equation of state
is based on the quark-diquark description of the single nucleon, while the
quark matter equation of state includes the effects of scalar diquark
condensation (color superconductivity). The effect of diquark condensation on
the phase transition is discussed in detail.
