Shakespeare and the Idea of Apocrypha offers the most comprehensive study to date of an intriguing but understudied body of plays. It undertakes a major reconsideration of the processes that determine the constitution of the Shakespeare canon through study of that canon’s exclusions. This thesis combines historical analysis of the emergence and development of the "Shakespeare Apocrypha" with current theorisations of dramatic collaboration. Several new theoretical and historical approaches to early modern authorship have emerged in the last decade. This thesis breaks new ground by bringing them together to demonstrate the untenability of the dichotomy between Canon and Apocrypha. Both within and without the text, the author is only one of several factors that shape the plays, and canonical boundaries are contingent rather than absolute. Chapter One draws on the New Textualism and studies of material print attributions, viewing the construction of the apocryphal canon alongside the growth of Shakespeare’s cultural prestige over three centuries. Chapter Two applies recent repertory studies to authorship questions, treating five anonymous King’s Men’s plays as part of a shared company practice that transcends authorial divisions. Chapter Three seeks dialogue between post-structuralist theory and "disintegrationist" work, revealing a shared concern with the plurality of agents within disputed plays. Within all three models of authorship, the divisions between "Shakespeare" and "not Shakespeare" are shown to be ambiguous and subjective. The associations of many disputed plays with the Shakespeare canon are factual, not fanciful. The ambiguity of canonical boundaries ultimately demonstrates the insufficiency of the "CompleteWorks" model for study of Shakespeare’s drama. Chapter Four confronts the commercial considerations that impose practical limitations on the organisation of plays. In so doing, this thesis establishes the theoretical principles by which the neglected plays of the Apocrypha can be readmitted into discourse, dispersing the fixed authority of the authorial canon.