Melvyn Bragg and his guests discuss the development of the microscope, an instrument which has revolutionised our knowledge of the world and the organisms that inhabit it. In the seventeenth century the pioneering work of two scientists, the Dutchman Antonie van Leeuwenhoek and Robert Hooke in England, revealed the teeming microscopic world that exists at scales beyond the capabilities of the naked eye. The microscope became an essential component of scientific enquiry by the nineteenth century, but in the 1930s a German physicist, Ernst Ruska, discovered that by using a beam of electrons he could view structures much tinier than was possible using visible light. Today light and electron microscopy are among the most powerful tools at the disposal of modern science, and new techniques are still being developed.With:Jim Bennett Visiting Keeper at the Science Museum in LondonSir Colin Humphreys Professor of Materials Science and Director of Research at the University of CambridgeMichelle Peckham Professor of Cell Biology at the University of LeedsProducer: Thomas Morris.