"Lincoln the Unknown is a biography of Abraham Lincoln, written in 1932 by Dale Carnegie. It is published by Dale Carnegie and Associates and given out as a prize in the Dale Carnegie Course.
Abraham Lincoln, a farm boy, becomes the President of the United States. He travels miles to borrow books; reading being the dominant passion of his for quarter of a century.
He mourns the loss of his first love his whole life. He humors his colleagues in the White House, and lives with the difficulties of the marriage with his second love, while in war with the South."

Dale Breckenridge Carnegie (November 24, 1888 - November 1, 1955) was an American writer and lecturer and the developer of famous courses in self-improvement, salesmanship, corporate training, public speaking and interpersonal skills. Born in poverty, Carnegie was the author of 'How to Win Friends and Influence People', first published in 1936, a massive bestseller that remains popular even today. He also wrote a biography of Abraham Lincoln, titled 'Lincoln the Unknown', as well as several other books. Carnegie was an early proponent of what is now called responsibility assumption, although this only appears minutely in his written work. One of the core ideas in his books is that it is possible to k change other people's behaviour by changing one's reaction to them.