This book argues against the legalisation of voluntary euthanasia and/or physician-assisted suicide on the ground that, even if they were ethically defensible in certain 'hard cases', neither could be effectively controlled by law. It maintains that the experience of legalisation in the Netherlands, Belgium and Oregon lends support to the two 'slippery slope' arguments against legalisation, the 'empirical' and the 'logical'. The empirical argument challenges the feasibility of drafting and enforcing adequate safeguards against abuse and mistake; the logical argument shows that acceptance of the case for euthanasia in the case of suffering patients who request it logically involves acceptance of euthanasia for suffering patients who are unable to request it, such as infants and those with advanced dementia.