In August 1906, Chauncey Canfield committed to his publisher a found text: the diary, ostensibly verified, of one Alfred T. Jackson, a pioneer miner who joined the Gold Rush from his home in Norfolk, Connecticut, migrating to Rock Creek, Nevada County, California, where he cabined and worked. The Diary covers two years of Jackson's life, and provides us with one of the richest documents of a period of perhaps unequaled importance to the expansion of the United States.

One of the most important and memorable events of the United States' westward push across the frontier came with the discovery of gold in the lands that became California in January 1848. Located thousands of miles away from the country's power centers on the east coast at the time, the announcement came a month before the Mexican-American War had ended, and among the very few Americans that were near the region at the time, many of them were Army soldiers who were participating in the war and garrisoned there. San Francisco was still best known for being a Spanish military and missionary...