Carl Linnaeus, today a largely unknown figure, is one of the giants of natural science. He devised the formal two-part naming system we use to classify all life forms. With Quentin Cooper is botanist Dr Sandra Knapp, from the Natural History Museum in London, life sciences expert Professor Staffan Müller-Wille from Exeter University in the UK, and science writer and biographer of Linnaeus, Dr Lisbet Rausing. Photo: Carl Linnaeus painted by Per Krafft the Elder (Permission of The Linnean Society of London)