Angle-resolved photoemission spectroscopy (ARPES) is a powerful material probe that offers insights in electron dynamics, correlations, and topology, in addition to direct probing of the electronic band-structure. Conventional ARPES processes involve the injection of photons into a material and the subsequent ejection of photoelectrons, which formerly occupied bound states in the material. This is known as the photoelectric effect. A natural question to ask concerns the underlying mechanism for photoemission and how information can be extracted from ARPES data. This talk will be a brief overview of this mechanism.