Dear comrades-descendants, the labourers of the 20th century are writing to you. Tell your children and grandchildren how we struggled for your right to immortality. We lived in heroic times when great discoveries were made, when the world was shaken by revolutions and wars burned the planet. […] You have probably already eliminated all harmful bacteria and viruses and live without ageing or sickness. But it was us who helped you in this, when we discovered the mysteries of cancer and overcame the barrier of tissue incompatibility.