The present volume contains the scientific contributions to the Fifth International Symposium on "Current Trends in Sphingo­ lipidoses and Allied Disorders" under the auspices of the Isaac Albert Research Institute of the Kingsbrook Jewish Medical Center, the Department of Pathology, Downstate Medical Center, State Uni­ versity of New York, Brooklyn, New York, and the National Tay-Sachs and Allied Diseases Association, Inc., New York. A review of the four previous Symposia shows the increase in scope of the scientific exploration in this rapidly expanding field. The first meeting, held in 1958, was devoted to the discussion al­ most entirely of Tay-Sachs disease. The majority of the work emanated from local laboratories. The participants at the present Symposium came from many other domestic and foreign research in­ stitutions. The scope of the papers presented at these meetings and the interest shown in the Symposium demonstrates the signifi­ cance attached by the scientific community to the problems of these hereditary diseases. The reasons for this are apparent, when one considers the contributions during recent years to our basic know­ ledge by lipid and enzyme chemistry, genetics, and neuropathology. Partly because of the hereditary nature of these diseases any new discovery in this field has general meaning and permits cautious generalization well beyond its clinical significance.