 We have noted that relative fundamentality is a very important notion, since the second key task for fundamentality identified above concerns the hierarchy of fundamentality. Moreover, relative fundamentality could arguably be used to define absolute fundamentality (some entity x is absolutely fundamental if and only if it is not relatively fundamental to any entity y). In contrast, relative fundamentality cannot be defined in terms of absolute fundamentality, so there are reasons to think that we should focus on relative fundamentality, insofar as the notion makes sense. Given this, it is perhaps surprising that there are relatively few explicit accounts of relative fundamentality in the literature so far, but we will refer to it where relevant (see Wilson 2012, 2016; Zylstra 2014; Koslicki 2015; Bennett 2017: Ch. 6; deRosset 2017; Correia forthcoming).