Book excerpt: The importance of polyamines for all living cells has been recognized since spermine was discovered in human semen more than 300 years ago. Polyamine research intensified when analytical methods were developed for their determination, particularly in tissues and biological fluids. Discovering their close correlation with cancer, and that polyamine concentrations change during the cell cycle, gave reason for further research in this topic. Polyamines in Health and Nutrition concentrates on the direction of polyamine research which has the capacity to influence and benefit our health and which can explain some of the discrepancies and failures of earlier research. It is important to recognize the dietary contribution to the polyamine body pool and to investigate how the polyamine content of the diet can be changed, with the ultimate aim of using this information to improve our health.