This inaugural edition of 'Tomorrow's World' includes three very different features. Derek Cooper, with help from consultant physician Dr Charles Fletcher, investigates new advances in kidney dialysis machines designed to work in the home and follows the range of opinions about this development. A second report looks at a Dutch flood defence system that has inspired plans in the UK to help ease a shortage of fresh water, while Professor Philip Morrison discusses the likelihood of the Mariner 4 space probe discovering evidence of life on Mars.