A new approach to heterotic moduli and dualities

<!--HTML-->In this talk I will review the way that the moduli of heterotic theories arise from a coupling of the geometry of Calabi-Yau manifolds and holomorphic, stable bundles over them. I will demonstrate that the complete geometry (manifold + bundle) of a heterotic theory can be described via a higher dimensional, toric complete intersection manifold and explain how this formulation may shed new light on heterotic string dualities.