I wish to thank the Board of Trustees of Trinity College, Dublin, for permission to publish Dillwyn's manuscript; also Dr Bernard Meehan and the staff of the Manuscripts Department for assistance rendered. Miss Maura Scannell, Head of Herbarium, National Botanic gardens, generously elucidated the numerous botanical references. Dr Kevin Whelan of the National Library, Dr Jim O'Connor and Dr Mark Holmes of the Natural History Museum also helped. The editor, Mr Diarmuid O Murchadha, provided much useful information.