Mie resonances in high index dielectric nanostructures have enabled a variety of novel nanophotonic concepts and technologies. For instance, Mie resonators are used in optical antennas, photodetectors, coatings, and metasurfaces. In this seminar I discuss my group’s recent research on Mie resonance engineering. I will demonstrate ultrawide tuning of infrared Mie resonators using electro-optic and thermo-optic effects in III-V and IV-VI semiconductors respectively. We tune Mie resonances by more than one linewidth using order-unity refractive index modulation, and show how such phenomena may enable reconfigurable metasurface devices. I conclude with an exploration of “forbidden” modes and new optical physics that emerge when Mie resonators are interrogated with unconventional light beams.