The conditions on early Earth prior to four billion years ago (Hadean Earth), which shaped the origin(s) and early evolution of life, are discussed in this chapter. It begins with a summary of the various sources of internal heat on terrestrial planets and the types of heat transport (e.g., conduction), as these factors influenced the habitability of early Earth and its temporal evolution. This is followed by an exposition of the characteristics of Hadean Earth: the Moon-forming impact, oceans, landmasses, and atmosphere, including the faint young Sun paradox – how did Earth stay unfrozen despite the Sun’s lower luminosity? The chapter concludes with sketching the putative Late Heavy Bombardment (a potential spike in the impactor rate) about four billion years ago, and a general treatment of the positives and downsides of large impacts.