In September 1991, Victor Zammit and I were in the Department of Biochemistry, the University of Cambridge, discussing ou r collaborative research project when we real ized thepotential value and need fora conference specifically concerned with fatty acid oxidation and ketogenesis. Thei dea, onceseeded, was indulged and flourished into the first Fatty Acid Oxidation & Ketogenesis (FAOx&K) Conference t hatwas held in the Department at Eastertime, 1992. Itw as attended byc olleagues mainly from the U. K. , France and Spain. From these modest beginnings atradition for holding a conference every second yearh asgrown and this Book results from the 4th International FAOx&K Conference that was held in London at the Institute of Child Health & Great Ormond Street Hospital forChildren NHSTrust, University College London Medical School in the new Conference Suite and was attended by colleagues from over twenty c ountries and five different c ontinents. I would like to thank allm y colleagues who havec ontributed to the conferences and, mos t importantly, to this Book. The first two c onferences were held in the University of Cambridge and were orga nized entirely by me but Simon Eaton, who came to work in London with me in Febru ary 1997,b ecame Conference Secretary andco organized the last two meetings. His contribution tot he conferences has been invaluable and w ithout hisdedicated help and effort neither the latermeetings n ort his Book would haveb een possible.