It became a hit after Cooke's death but it was an early protest song and many say it was Cooke's greatest compilation. He was born in Mississippi and took an active role in the civil right's movement. This song is said to have exemplified the 60's Civil Right's Movement. Here is some info on it:
Cooke was greatly moved upon hearing Bob Dylan's "Blowin' in the Wind" in 1963 and was reportedly in awe that such a poignant song about racism in America could come from someone who was white. While on tour in May 1963, and after speaking with sit-in demonstrators in Durham, North Carolina following a concert, Cooke returned to his tour bus and wrote the first draft of what would become "A Change Is Gonna Come."
In a sense, "A Change Is Gonna Come" is an answer to Dylan's "Blowin' in the Wind", as well as a song of hope for the Civil Rights Movement. The hypothetical questions posed by Dylan, most obvious being "how many years can some people exist, before they're allowed to be free?", were answered by an implied "Fewer than you think." Though Cooke recognized "it's been a long/a long time coming", the song states that change is inevitable. A similar sentiment was echoed by Dylan in "The Times They Are a-Changin'", written and released after "A Change Is Gonna Come."
"A Change Is Gonna Come" also reflected much of Cooke's own inner turmoil. Known for his polished image and light-hearted songs such as "You Send Me" and "Twistin' the Night Away", he had long felt the need to address the situation of discrimination and racism in America, especially the southern states. However, his image and fears of losing his largely white fan base prevented him from doing so.
The song, very much a departure for Cooke, reflected two major incidents in his life. The first was the death of Cooke's eighteen-month-old son, Vincent, who died of an accidental drowning in June of that year. The second major incident came on October 8, 1963, when Cooke and his band tried to register at a "whites only" motel in Shreveport, Louisiana and were summarily arrested for disturbing the peace. Both incidents are represented in the weary tone and lyrics of the piece, especially the final verse: "there have been times that I thought I couldn't last for long/but now I think I'm able to carry on/It's been a long time coming, but I know a change is gonna come."
It was featured in the movie, Malcom X, which I think is a good indicator of the song's intent and meaning about a deep sense of unrest within him.
http://www.youtube.com/watch?v=4qyWIGu5Ryk