  This analysis of the electroclinic effect in ferroelectric liquid crystals
with a first order Smectic-$A^*$--Smectic-$C^*$ (Sm-$A^*$--Sm-$C^*$)
transition, shows they can be either Type I or Type II. In temperature--field
parameter space Type I systems exhibit a macroscopically achiral (in which the
Sm-$C^*$ helical superstructure is expelled) low-tilt (LT) Sm-$C$--high-tilt
(HT) Sm-$C$ critical point, which terminates a LT Sm-$C$--HT Sm-$C$ first order
boundary. This boundary extends to an achiral-chiral triple point where the
achiral LT Sm-$C$ and HT Sm-$C$ phases coexist with the chiral Sm-$C^*$ phase.
In Type II systems the critical point, triple point, and first order boundary
are replaced by a Sm-$C^*$ region, between LT and HT achiral Sm-$C$ phases, at
low and high fields respectively. When the field is ramped up, the Type II
system displays a reentrant Sm-$C$--Sm-$C^*$-Sm-$C$ phase sequence. A
discontinuity in the tilt of the optical axis at each of the two phase
transitions means the Type II system is tristable. The system is Type I or Type
II depending on the ratio of two length scales, one is the zero-field Sm-$C^*$
helical pitch, the other depends on the latent heat at the zero-field first
order Sm-$A^*$--Sm-$C^*$ transition. A system could be experimentally tuned by
varying enantiomeric excess, between Type I and Type II behavior. We also show
this Type I vs Type II behavior is the Ising universality class analog of Type
I vs Type II behavior in XY universality class systems. Lastly, we make a
complete mapping of the phase boundaries in temperature--field--enantiomeric
excess parameter space (not just near the critical point) which shows a variety
of interesting features, including a multicritical point, tricritical points
and a doubly reentrant Sm-$C$--Sm-$C^*$-Sm-$C$--Sm-$C^*$ phase sequence.
