Thomas Roy was a civil engineer and geologist who lived in Toronto from 1834 to 1842; he was probably Canada's first geotechnical engineer. In 1835 he carried out the survey for what would have been Canada's first railway if it had then been constructed. He acted as City Engineer for the fledgling city. Nothing is yet known of his life before 1834 but the search continues. In 1837 he presented to the Geological Society of London a paper on the former, raised water levels of the Great Lakes, based on his field observations while surveying. In 1841 he wrote and had published a remarkable little book on road making, in some ways far ahead of its time; significant extracts are herein presented.Key words: road building, archival, geology.