This chapter describes the major features of the prompt radiation fields produced by electrons. It also discusses the development of the electromagnetic cascade and the shielding of photoneutrons and high-energy particles. The utilization of Monte Carlo calculations in electron shielding problems is also addressed. Bremsstrahlung is the radiative energy loss of charged particles, especially electrons, as they interact with materials. It appears in the form of photons. Some of the information in this section is also useful in understanding the radiation produced by certain accelerator components, such as radiofrequency cavities operated apart from the main accelerator, as pointed out by Silari et al. Neutron production can be expected to occur in any material irradiated by electrons in which bremsstrahlung photons above the material-dependent threshold are produced. This neutron production threshold varies from 10 to 19 MeV for light nuclei and 4–6 MeV for heavy nuclei.