Harmon spent nineteen years as an explorer for the North West Company in the present provinces of Saskatchewan, Manitoba, Alberta, and British Columbia. He kept this account of his travels and adventures "partly for his own amusement, and partly to gratify his friends, who he thought, would be pleased to be informed, with some particularity, on his return, how his time had been employed, during his absence." Harmon's personal impressions of the life of an explorer, therefore, were far more vivid than those recorded in the often dull, official business documents kept by many of his colleagues.
Unfortunately, the integrity of Harmon’s account had been clouded by the pious efforts of the book’s editor, Rev. Daniel Haskel, who stated:
"The following work was furnished to my hand fully written out; and though I have written it wholly over, I should have been much better able to satisfy myself, with respect to its style, if I could as fully have possessed the materials, in the form of notes and sketches, or by verbal recitals."
However, Haskel's labors for a literary, as well as a moral narrative, did not alter the original character of simplicity and authenticity intended by Harmon. The last entry is dated August 18, 1819.
To counteract his "World of disappointments and sorrows," Harmon frequently exchanged letters with neighboring fur traders, noting their activities in his journal. Thus we have recorded the achievements of many influential men, such as David Thompson, Simon Fraser, Roderick McKenzie, and John Stuart.
One such passage from the manuscript copy of Hannon's journal anticipated, perhaps, the most important of all North American exploratory adventures:
November 24, Saturday  A Man arrived from Montagne a la Basse, with a letter from Mr. Chaboillez which informs me that two Captains Clarke & Lewis & one hundred & eighty Soldiers had arrived at the Mandelle [i.e. Mandan] Village on the Missisouri [sic] River -- who invite Mr. Chaboillez to go & pay them a visit (which is only a distance of five or Six Days march from where he is). It is said that on their arrival there they hoisted the American Flag and told the Natives that they were not come among them to traffic, but merely to see the Country, and that as soon as the navigation was open they should continue their route across the Rocky Mountains & then down to the Pacific Ocean. They also made the Natives a few trifling presents, as well as repaired their Guns & Axes &c gratis. Mr Chaboillez writes that they behave remarkably honourably towards his people who are there to traffic with the Natives. This page is presented below.