Microcrystal electron diffraction (MicroED) is a cryoEM method for determining the 3D structure of inorganic, organic, or biological macromolecules. Compared to X-rays or neutrons, electrons exhibit a stronger interaction with the sample and cause considerably less damage per useful elastic scattering event. Thus, the optimal crystal size for MicroED is well below 1 µm³, and even crystals consisting of only a few layers can be used for structure determination. In fact, electron diffraction is currently the only method that can routinely produce a complete diffraction dataset for samples of this size and can be acquired with only picograms of a sample. This contrasts with X-ray free-electron laser (XFEL) serial crystallography and serial synchrotron crystallography (SSX), which require hundreds of thousands of crystals, with the crystals needing to be larger than 1 µm and 5 µm, respectively. Ultimately, crystallographic techniques that use electrons, X-rays, or neutrons are complementary because the beams interacting with the sample have different sensitivities for various elements. Moreover, MicroED and neutron crystallography can visualize hydrogen atoms, which are often not possible with X-ray crystallography due to their relatively small cross-section with X-rays. Finally, electron diffraction can provide information on charge.