I just finished Undaunted Courage by Stephen Ambrose. This book tells the story of the Lewis and Clark expedition to the west. It's an interesting snapshot of the history of our country. While Lewis and Clark are considered to be the "first" white men to explore the west, actually, French and English traders had already trekked through the country, mostly heading south from Canada.
Lewis and Clark did, however make a great contribution to our history. While they did not succeed in their mission to find an unobstructed water way to the Pacific, they did make many scientific discoveries and convinced several indian nations that the U.S. was friendly (in 1804-05, the U.S. was indian-friendly. Later, the progress of the country changed the indian policy).
Ambrose's book goes into great detail on Lewis' personality. While a great explorer, Lewis suffered from deppression and was hooked on drugs and alcohol. After returning from the expedition, he was appointed governor of the Louisiana territory, but he failed at this job, along with failing to ever get his journals published. He depression eventually led to his suicide in 1809.
The book also provides some interesting history on Thomas Jefferson, the president who most pushed for western expansion.
In all, a very good book which provides great insight into our history. I also have a copy of Nothing Like It in the World, Ambrose's account of the building of the TransContinental Railroad. I plan on reading that next.