How does nature change through time and across space? How might it change in the future? While time travel has long been the domain of science fiction, scientists have approached these questions using techniques that examine the traces of the past remaining in today’s environment. The use of ancient environmental DNA (ancient eDNA) is the latest method for paleoenvironmental reconstruction in a line of ancient biomolecular research, with the first research into DNA barcoding appearing near the turn of the last century (Willerslev et al. 2003). This field has principally advanced through a combination of milestone discoveries and a technological revolution that ultimately transformed genetic and genomic analyses into the Big Data Science we recognise today (Fig. 13.1). But what has been the trajectory of this development, and perhaps more importantly, what future potential lies ahead for this research area?