MMS has observed several electron and ion diffusion regions of magnetic reconnection in the Earth’s magnetotail. These observations include accurate 3D electric and magnetic fields and ion and electron distributions. The initial results confirm that, inside of the electron diffusion region, the kinetic behavior of electrons develops a gradient in an off-diagonal term in the electron pressure, which supports the reconnection electric field. Essentially, electrons only dwell in the electron diffusion region for a finite period and carry the momentum (gained for the reconnection electric field) out of the electron diffusion region via transverse motion. This major finding of MMS appears to unveil a detailed mechanism of collisionless magnetic reconnection. However, the large-scale behavior due to magnetic reconnection requires further investigation. Magnetic reconnection appears to incite strong particle acceleration and turbulence in the magnetotail. I will discuss what we know and what we do not know about magnetic reconnection in the Earth’s magnetotail.