  We explore the moduli space of the two dimensional fermionic string with
linear dilaton. In addition to the known 0A and 0B theories, there are two
theories with chiral GSO projections, which we call IIA and IIB. They are
similar to the IIA and IIB theories of ten dimensions, but are constructed with
a different GSO projection. Compactifying these theories on various twisted
circles leads to eight lines of theories. Three of them, 0A on a circle,
super-affine 0A and super-affine 0B are known. The other five lines of theories
are new. At special points on two of them we find the noncritical superstring.

High Energy Physics - Theory