The Royal Society of London for Improving Natural Knowledge has been at the forefront of scientific endeavour for more than 350 years, since receiving its royal charter from Charles II in 1662. Philosophical Transactions, published in 1665, established the concepts of scientific priority and peer review and is the oldest scientific journal in continuous publication in the world. The 8,000 fellows elected to the Society to date include all of the scientific leading lights of the last four centuries, including Isaac Newton, Charles Darwin, Tim Berners-Lee and Stephen Hawking. The Society's motto, nullius in verba, 'on the word of no one', is a reminder of its founders' belief that authority must always be questioned; hypotheses can never be taken for granted; truths must be demonstrated or they are not truths at all. Adrian Tinniswood examines why the Royal Society has been such a pivotal institution in the cultural life of Britain and the world.