This history of the O'Nolans would not have happened but for a series of peculiar events. He, himself, had Co. Carlow roots and, in the course of correspondence, was called cousin' by the O'Nolans of Ballinrush, Myshall, Co. Carlow. During his quest for information about the Nolan sept he visited Co. Carlow quite frequently. His manuscripts and letters were passed on to Fr. Swayne, P.P. of Clonegal, a noted scholar, for completion and possible publication, but he was unable to find the time to finish the work before he passed away. A cousin of Mary FitzSimons, and felt that I might be in a position to bring the work to fruition, because of my knowledge of the period and because of my treatment of the Kavanagh material. He wrote to me in 1996/97 and urged me to get in touch with Mary FitzSimons. I did this and was given custody of the material, without promising anything other than to look at the documents.My first job was to sort out the papers and I found out that Fr. Nolan had in fact written about 15 or 16 chapters dealing with the history of the sept beginning with the origins of the O'Nolans in prehistory and coming right up to the 17th. century. Still undecided, I contacted , the late Tom Nolan of Slyguff, Mary FitzSimons and my friend Jim Nolan of Ballinrush. Through a contact called , I got to know who was planning to honeymoon in Ireland. We all met in Bunclody in January of 1998. All present urged me to undertake the work and the members of Clan Nolan offered their full support. I feel the book is a special tribute to Fr. Nolan who must have spent such a huge amount of time in compiling and working with the data in those days when computers had not even been dreamt about. Without the input from all those people this book would not have been written.