Professor Sir David Smithers introduces on the curability of cancer. The most dramatic example of the increasing success of the new treatments is in children. In leukaemia, the most tragic of all cancers, can we now begin to talk about cures? On prevention: Lung cancer is not only the major preventable cancer - it is the major cancer in men - DR MALCOLM PIKE What has been achieved in the 20 years since the physicians' report on smoking and cancer of the lung? And are there other cancers that we could prevent more easily? On new ways of detecting cancer: It is quite clear that we are at the tip of the iceberg - I am very optimistic about this-PROFESSOR PETER ALEXANDER If breast cancer Is discovered early enough, four out of five women can be treated successfully - and yet the Department of Health has said that there is to be no national screening service. Why? Could delay in reporting symptoms - a major cause of death - be reduced by the hope of simpler treatment? This documentary shows that few of these questions have simple answers. But in each case there is progress to record - and, in all, real hope for the future. Narration read by DEREK JONES Written and produced by ALEC NISBETT