Handbook of Psychopharmacology: Volume 20: Psychopharmacology of the Aging System Book Description Leslie L Iversen has contributed to Handbook of Psychopharmacology: Volume 20: Psychopharmacology of the Aging System as an editor.Leslie Iversen is Professor of Pharmacology at Oxford, and was previously Director of the Neuroscience Research Centre of Merck Research Laboratories. His most recent book is The Science of Marijuana, published by OUP. Solomon H Snyder has contributed to Handbook of Psychopharmacology: Volume 20: Psychopharmacology of the Aging System as an editor.Solomon H. Snyder, M.D., is Distinguished Service Professor of Neuroscience, Pharmacology, and Psychiatry at Johns Hopkins University.