John Walker, DD, born in Edinburgh, was a gifted scholar who showed early brilliance, reading Homer fluently by age ten. Ordained in the Church of Scotland, he served first at Glencorse, where his passion for botany and natural history flourished through extensive fieldwork in the Pentland Hills. His scientific reputation led to missions across the Highlands and Hebrides, resulting in valuable research later published as An Economical History of the Hebrides. Appointed Professor of Natural History at the University of Edinburgh in 1779, Walker played a foundational role in establishing the subject there, delivering well-regarded lectures and contributing widely to learned societies. Though known publicly for his formality and eccentricities, he was sociable in private life and deeply devoted to science until his death in 1804, leaving behind important collections and a lasting legacy in Scottish natural history.