Concerning Lincoln as the Great Emancipator: Lincoln issued the Emancipation Proclamation about a year after he began making war upon the CSA. He did not want to upset any of the slaveholders in Ky. or Md., so he did not declare the slaves in those states free. He did not want to upset any of the slaveholders in those parts of CSA which were already controlled by his armies, so he did not declare the slaves in those areas free. He declared free only the slaves in areas of the CSA that his armies did not control, so actually he did not free any slaves, but as Lincoln's armies moved further into the CSA, many of the slaves freed themselves by putting their feet in the road and leaving.
Lincoln did try, in his Emancipation Proclamation, to incite the slaves in the CSA to rebel against their masters by declaring that if in doing so, any of them committed acts that normally would be considered criminal, they would not be prosecuted for those acts when and if his armies arrived. The slaves, though, were more civilized than he gave them credit for; none of them committed any acts of violence as he had hoped they would.
Concerning Lincoln's life: He grew up poor. He gained little of the knowledge of history and philosophy of government that was considered a part of a good education. He did become a lawyer and was a lawyer for big industry (railroads).
He married Mary Todd, daughter of a Ky. planter. The first time they were to be married, he stood her up. He did not show up for his own wedding. Somehow, she forgave him and they were married later.
He was a very intelligent man who could often illustrate important truths and insights about life by telling folksy tales that everybody could understand. He also liked to tell dirty jokes. When he gave political speeches, he phrased them so that they sounded like passages out of the King James Bible; this influenced a lot of listeners to believe what he said just because of the way it sounded.
Some people think he did not understand compassion. For example, when Souix Indian residents of Wisconsin rebelled because the state and local governments and the local white citizens were severely abusing them, many of them were sentenced to be hung. An appeal was made to Lincoln and he said 'hang just half of them'; not very compassionate considering the justice of their cause.
Concerning Lincoln's views on slavery: He wanted to free the slaves and then send them all to Africa or Central America. He gradually realized that this would be too expensive. He did not think that blacks were socially or intellectually equal to whites, but he did not think that it was right to prevent any man from looking for a better job if he was qualified. He did not want to free the slaves only out of justice to them but also in order to destroy the southern aristocracy so that northern industrialists and the Republican party would have unchallenged rule of both the U.S. government and the southern resources (land, cotton, freed black laborers). He did put politics ahead of any sense of justice; he declared as another answerer has stated, that he would free none of the slaves, if keeping them in slavery would win him his war.
Abraham Lincoln was considered the "Great Emancipator" because of the Emancipation Proclamation. It applied to the confederate states that had seceded from the Union. The freedom that the Emancipation Proclamation promised was dependent on a Union victory in the Civil War. President Lincoln did not believe in slavery and believed in personal freedom. He thought it was morally wrong to treat individuals in the manner that the slaves were often treated.
In his own words, here is what Abraham Lincoln had to say about his own life:
"I was born Feb. 12, 1809, in Hardin County, Kentucky. My parents were both born in Virginia, of undistinguished families--second families, perhaps I should say. My mother, who died in my tenth year, was of a family of the name of Hanks.... My father ... removed from Kentucky to ... Indiana, in my eighth year.... It was a wild region, with many bears and other wild animals still in the woods. There I grew up.... Of course when I came of age I did not know much. Still somehow, I could read, write, and cipher ... but that was all."
There is a link posted below that contains several quotes by Abraham Lincoln and his views towards slavery.
He was so-named this after he announced the Emancipation Proclamation, which freed the slaves in the South and territories not under Northern control. It was symbolic at first, since initially the South did not enforce the Emancipation order (they were in open rebellion against the North)
Later, as the Northern troops took more territory the emancipation was able to be enforced. This title also is accurate since Lincoln wished to make Slavery illegal by law. Though he was killed before it was passed as law, Lincoln supported plans for the 13th Amendment.
As mentioned in the other response post, Lincoln had his personal views and his political views. Both views saw a natural evolution where he came to believe Slavery morally wrong and then making Slavery illegal as a political goal.
He was criticized while president for doing too little and not doing enough as well as changing the war goals.
Hope this helps.
You can say that Lincoln was the Great Emancipator because he is the one who issued the Emancipation Proclamation and because he was extremely determined to actually defeat the Confederacy rather than making some kind of deal with it that would continue to allow slavery.
As far as his views, he was personally very opposed to slavery. Politically, he was opposed to the extension of slavery. He was okay with letting it continue in the South (didn't think it was constitutional to force them to end it) but he did not want it to spread out into areas where it did not yet exist.
A very famous quote of his from the war is that he cared only about the Union and that he would save it by freeing no slaves, some slaves, or all the slaves. What was important was saving the Union.