First published in 1849 and later revised in several subsequent editions, Francis Parkman&rsquo;s&nbsp;<i>The Oregon Trail</i>&nbsp;is the definitive trail-journal. The author was 23 when he stepped on a steamer and began a two-month tour through the West, visiting Nebraska, Wyoming, Colorado, and Kansas. A historian, Parker was determined to articulate his trail experiences in the most informed manner possible, and his book was a best-seller.