This work attempts to provide a critical guide to the written sources for early modern Irish history: 1534–1641. The task of researchers in this area was made particularly difficult by the burning of much relevant documentary material in the Public Record Office of Ireland at the beginning of the Irish civil war in 1922 and by the destruction of other records before and since then. The problem of the loss of documents has to a large extent determined the way in which this volume has been organised. The first four chapters assess the administrative sources, civil and ecclesiastical, central and local, Irish, English and foreign. The approach in these chapters is administrative in order that all the documentation produced by early modern institutions in Ireland or elsewhere in relation to Ireland can be noted. This enables the surviving documentation to be fitted into an administrative context and emphasises the need to consider the surviving documents in relation to what has been destroyed. The approach in the next two chapters is chronological as the contemporary writings, maps and drawings are described. The references in these chapters are necessarily selective but the chronological arrangement allows the most significant types to be noted. In chapter seven archival collections with early modern material are briefly described. The large number of repositories listed here was considered necessary because of the destruction of so much of the archives of the central and local Irish administrations. Many of the documents noted here are not archival in the strictest sense of the word, for which reason it was thought useful to indicate where possible the provenance of the documents noted.