Geometric quantization and the quantization commutes with reduction principle have been studied intensively for decades, having its origins in physics. In their 1982 paper, Guillemin and Sternberg conjectured that quantization commutes with reduction when both the symplectic manifold and the symmetry group is compact, proving it in an important special case. The general case was proved by Meinrenken in 1998, and shortly thereafter, a direct analytic proof was given by Tian-Zhang based on the Witten deformation technique. In 2005, Hochs and Landsman formulated the quantization commutes with reduction principle when both the symplectic manifold and the symmetry group was noncompact, but the quotient was assumed to be compact, and provided evidence for their conjecture. An asymptotic version of the Hochs-Landsman conjecture was proved in [MZ08] by adapting the Tian-Zhang approach. In [HM13] the Hochs-Landsman conjecture was proved completely, and the quantization commutes with reduction principle when the quotient is noncompact (but the reduction is compact) is formulated and evidence given of its validity. The method used is an adaptation of the Tian-Zhang approach. In [HM14], we generalize the formal geometric quantization of Weitsman, to the case of proper actions of noncompact groups acting on prequantizable symplectic manifolds and establish various functorial properties of formal geometric quantization. In [HM14-2], we prove the most general quantization commutes with reduction principle, now for noncompact equivariant Spinc-manifolds, where the group is a unimodular connected Lie group.