At age 75, David Thompson began to write about his life of exploration and surveying in western North America from 1784 to 1812. At this point, how-ever, the odds of? nishing were slim; his eyesight was failing, his body was worn out after years of strain on portages and mountain passes. For? ve years he toiled with rewrites and revisions, never able to set the? nal account in order. On 16 January 1851 he put his 'papers to right' in one last attempt to? nish his work. By 28 February 1851, no lo