In one photograph, on a balcony above the stands, a young man with a black mustache and wearing a top hat gazes down on the president. It is the famous actor John Wilkes Booth.
-- Narrator (Prologue paragraph 2)

Importance: This indicates that Booth was granted admission to the president's inner circle without question. Booth was famous and he could have killed the president on this day. The fact that he sets up an elaborate plan indicates that he really doesn't want the assassination to be a suicide mission.

Twenty-six years old, impossibly vaid, an extremely talented actor, and a star member of a celebrated theatrical family, John Wilkes Booth was willing to throw away fame, wealth, and a promising future for the cause of the Confederacy.
-- Narrator (Chapter 1 paragraph 3)

Importance: This is an important look at Booth and his devotion to the Southern cause, which is why he was willing to risk his life in order to kill Lincoln...