The proceedings of this festschrift, in honour of Edward Johns on his retirement from the Chair of Physiology at University College Cork, contains reviews of current and past research on the neural and humoral control of the kidney by his collaborators and colleagues. The very nature of a festschrift, containing accounts both of the science and the personal interactions between colleagues, has allowed the authors to get away from the impersonal modern style of reporting research findings and to convey the excitement of research, the cut and thrust of debate and the lows and highs when a treasured hypothesis is falsified or corroborated by well designed experiments.The chapters cover a wide range of topics in renal physiology written by authors who have been directly involved in experimental renal physiology at sometime or throughout their careers and thus both past and recent research is reviewed. The emphasis throughout is on heart brain kidney interactions and the topics range from a mathematical analysis of renal sympathetic nerve activity (Tao Zhang) to the new and exciting use of renal denervation for the treatment of hypertension in man (GF DiBona). Other topics covered are the role of renal afferent nerves in sodium homeostasis (Ulla Kopp); a review of recent research on heart brain kidney interactions (JH Coote); atrial receptors and the kidney a search for a diuretic hormone (HM Snow); cardio-renal reflexes and body fluid homeostasis (Kenju Miki); sodium intake, brain angiotensin and the development of hypertension (Belinda McCully); adrenoceptor activation and sepsis induced renal inflammation (Akio Nakamura).