context: Various approaches have been employed to address these issues through the engineering of ex situ deposited surface coatings, solid electrolyte interphase (SEI) transplantation, electrolyte additives, and 3D host materials. These studies have been largely empirical with limited effort directed towards a fundamental understanding of the interplay between electrolyte composition, SEI formation, and lithium metal morphology. For example, it is important to quantify the amount of lithium lost into the SEI, soluble reduction products, “dead” lithium, and corrosion, and to identify how these loss mechanisms are mitigated by using additives or surface coatings. This knowledge will enable the development of commercially viable solutions. Empirical approaches have had some success in improving coulombic efficiency and cycle life, but in most cases it is unclear which loss mechanism is mitigated and how. We consider understanding these processes mechanistically to be the “Holy Grail” of lithium anode research, knowledge that may be extensible to other battery chemistries.