Interactions between emitters and nanophotonic structures are of central importance in contemporary optical science. Many devices in the želds of sensing, quantum information processing, and plasmonics, among others, may be modeled as dipoles interacting with some (possibly complex) medium. However, despite its fundamental importance, the problem of a dipole radiating in the presence of dielectrics is surprisingly nontrivial and has been the subject of a large body of research dating back to over a century. Even the most simple case-a dipole over a dielectric half-space-has required many decades to work out, with Sommerfeld, Weyl, Zenneck, and Norton among the many contributors [1-4].