I describe recent work towards developing non-supersymmetric string
theory as a phenomenological framework in which to embed the Standard Model. Chief among the issues that have to be solved in the absence of supersymmetry are stability and naturalness. I describe how they can be tackled using a Scherk-Schwarz compactification that allows supersymmetry to be parametrically broken (and the theory to be parametrically badly behaved). Being UV complete and one-loop finite the framework allows one to revisit various field theory ideas about naturalness (such as the so-called Veltman condition) to see if they make sense.