How did secession come about, and where did the sentiments for it originate? Discuss the Upper South's reaction to the secession of the Lower South?

How did secession come about, and where did the sentiments for it originate?
Discuss the Upper South's reaction to the secession of the Lower South?
According to Jefferson Davis, what was the South fighting for, and what did they need to do to achieve independence?
Why did Lincoln dismiss General McClellan?
What did "total war" mean in the context of the Civil War?
Briefly, how did the North and South mobilize resources with which to fight the war? How was the war financed?
What was contraband, and how was it controversial?
Why did Lincoln issue the Emancipation Proclamation when he did and what did it mean?
What were the consequences of the victories at Vicksburg and Gettysburg happening at the same time?
After Vicksburg, what did Grant think of the "cautious tactics of previous Union commanders"?
What was General Sherman's "hard war," what was his "bold strategy" after taking Atlanta, and how did he justify his unconventional plan to Grant and Lincoln?
What was the reasoning behind the need for the Thirteenth Amendment?
Was the Civil War necessary? Many argue that it was not, that slavery would have died out within a few decades (it certainly would have, that's unquestionable), and that the war was a tremendous loss of money, lives, and resources that could have been avoided. What do you think?