Answer:
I think you should leave it as is. You italicize words to stress a meaning but to my knowledge, nothing needs stressing in that sentence. Hope it helps and sorry if it didn't. ♥ 
 
        
             
        
        
        
The author who would become famous as Mark Twain started out in life as Samuel Clemens. Born and raised along the Mississippi River, Clemens would start out in life as a steamboat pilot.
This book, which was written after he was a famous writer, tells the story of his life on the river. In the first part, he is a cub pilot under his mentor, Horace Bixby, who teaches him how to navigate the treacherous river. The very very wordy Twain mixes it up in this part of the book, describing both the river, steamboats, steamboating, etc., and what happens to him as a pilot. This is an interesting part of the book because it includes a fair amount of commentary about life in America after the Civil War, reflecting on the differences between the North and the South.