I will discuss recent multi-wavelength observations of cool stars, with an emphasis on how radio and X-ray observations provide independent but complementary views of the structure and variability of coronal outer atmospheres. Topics will include: radio and X-ray observations of stellar flares and the evolution of flaring plasma; signatures of coherent emission in the coronae of active stars; investigations of coronal structures using X-ray, radio and optical observations; radio and X-ray observations of ultracool stars/brown dwarfs; consistency between radio and X-ray observations of thermal bremsstrahlung emission from the atypical case of Capella.