How should judges go about assessing the admissibility of evidence? In this Article, I explore a key and underexamined issue within evidence law: the interpretive tension between atomism and holism. Should judges assess the admissibility of an item of evidence atomistically—piece by piece, and by itself? Or should they engage in a more holistic, synthetic, and relational inquiry? I argue that there is not, and cannot be, any simple answer to this question, because judicial atomism versus holism turns out to implicate two further important tensions within our bifurcated trial system: the balance of power between the judge and the attorney, on the one hand, and between the judge and the jury, on the other. Moreover, the relation between these multiple issues turns out to depend significantly on whether the evidentiary assessment at issue is what I term a low-threshold evidentiary determination, tilted in favor of admissibility (like relevance, or Rule 403), or, instead, a high-threshold determination (like the assessment of expert evidence). This Article explores both an array of evidence doctrines and the extent to which they provide guidance to judges vis-à-vis atomism versus holism, and then looks in detail at how atomism versus holism operates in both low-threshold and high-threshold circumstances.