I wish to thank Dr David Dickson of Trinity College Dublin for drawing attention to Dillwyn's manuscript and the Board of the College for permission to publish it. I owe a special debt of gratitude to Miss M. Scannell, Head of Herbarium, National Botanic Gardens, for elucidating the numerous botanical references. The following also helped: Peter Tynan O'Mahony, Secretary, O'Mahony Records Society; Dr Breandán Ó Cíobháin, Coimisiún na Logainmneacha; Breandán Breathnach, Na Píobairí Uilleann; Dr Pádraig de Brún, Dublin Institute for Advanced Studies; Rev. Fr Kieran O'Shea, Castleisland; Mr Danny Moriarty, Kenmare; Dr Noel Kissane, Mr Brian McKenna and Peadar Mac Mathúna, National Library; Dr Jim O'Connor and Mr Mark Holmes, Natural History Museum; Mrs K. Browne and Mrs Margaret O'Riordan, Kerry County Library.