This chapter starts to analyse the institutional frameworks of different international courts and tribunals in comparative perspective. More importantly, it introduces the invisible army of legal bureaucrats (clerks, registry and secretariat officials, and arbitral secretaries) who assist international adjudicators in their daily duties. The story focuses on their backgrounds, their modes of recruitment and promotion, their relationship with the judges and arbitrators they are called to serve, and the ambiguities inherent in that relationship. From here onwards, the role of bureaucrats in the judicial process will come into sharper relief. Their duties typically include: summarizing the parties’ arguments for the benefit of the adjudicators, conducting legal and factual research on the disputed issues, circulating internal memoranda that suggest options on how to solve the case, assisting in the preparation of oral questions for hearings, attending deliberations, and drafting the final judgments or awards.