A large number of the photographs from which this volume is illustrated were taken by him and they speak for themselves.

Thompson was from Illinois.
He also had been a soldier in the war, and on this expedition was Powell's colleague, as well as the geographer.

To his foresight, rare good judgment, ability to think out a plan to the last minute detail, fine nerve and absolute lack, of any kind of foolishness, together with a wide knowledge and intelligence, this expedition, and indeed the scientific work so admirably carried on by the United States Survey of the Rocky Mountain region and the Geological Survey for three decades in the Far West, largely owe success.

Steward was an old soldier, was from Illinois, and went with us as geologist, assisting Powell himself in this line.

Bishop had been a captain in the war, had been shot through and through the left lung, and was an enthusiast in Western exploration.
He was one of the topographers.