Walter Murray was a young man tired of living in the city. Early in the 1920s, he persuaded a Sussex farmer to rent him a derelict cottage, which stood alone on a hill, with no running water or electricity. Most of the windows were broken, it was dirty, dark and ran with rats. He bought a brush and pail in the village, forced the rats to retreat, brought in rudimentary furniture. The local postman found him a dog, and with his new companion he began to explore his surroundings. In that year at Copsford he made a living from collecting, drying and selling the herbs he found locally:...