In 1858, aged thirty-five, weak with malaria, isolated in the remote Spice Islands, Alfred Russel Wallace wrote to Charles Darwin: he had, he said excitedly, worked out a theory of natural selection. Darwin was aghast - his work of decades was about to be scooped. Within a fortnight, his outline and Wallace`s paper were presented jointly in London. A year later, with Wallace still at the opposite side of the world, ”On the Origin of Species” was published. Wallace had none of Darwin`s advantages or connections. Born in Usk, Gwent, in 1823, he left school at fourteen and in his mid-twenties spent four years in the Amazon collecting for museums and wealthy patrons, only to lose all his finds in a shipboard fire in mid-Atlantic. He vowed never to travel again. Yet two years later he was off to the East Indies, beginning an eight-year trek over thousands of miles; here he discovered countless unknown species and identified for the first time the point of divide between Asian and Australian fauna, `Wallace`s Line`. With vigour and sensitivity, Peter Raby reveals Wallace as a courageous and unconventional explorer.After his return, he plunged into a variety of controversies, staying vital and alert until his death at the age of 90, in 1913. Gentle, self-effacing, and remarkably free from the racism that blighted so many of his contemporaries, Wallace is one of the neglected giants of the history of science and ideas. This stirring biography - the first for many years - puts him at centre stage, where he belongs.