This lecture covers the early history of radio astronomy, focusing on the innovations made by Martin Ryle and his colleague Vonberg in the UK. They developed radio interferometry using two antennas to study the Sun and the Milky Way, leading to Ryle winning the Nobel prize in 1974. The lecture also discusses the discovery of pulsars by Jocelyn Bell and the cosmic microwave background by Penzias and Wilson, highlighting key breakthroughs in astrophysics and cosmology.