Recent headlines like these have turned public attention again to one of medicine's most poignant problems - deciding when treatment has to stop. The use of life-support machines is just one area where doctors have to make crucial decisions. Specialists sometimes have to decide how to deal with the chronic difficulties that occasionally develop in old age; and the fortunately rare but often appalling congenital deformities that are on occasions discovered at birth. And yet there's little dispute amongst doctors about the medical decisions involved; what they actually do is probably not realised by most of us. Why is their role so widely misunderstood and misreported? Tonight, with Jack Pizzey and Harold Williamson in the studio, some doctors explain their approach, and next-of-kin give their views. Others, detached observers like Lord Soper and Marjorie Proops , will be listening carefully in an attempt to penetrate the misunderstandings and to suggest what, if anything, should be done