Following his assassination, the civil rights advocate's popularity was revived by hip-hop artists in the late 1980s and early '90s and his image began appearing on clothing, college dorm posters and eventually in a Spike Lee 1992 biopic.

Now a Smithsonian Channel documentary is examining the life of Malcolm X through rare footage from his speeches and media interviews to let the slain leader speak to a new generation using his own words.

"The Lost Tapes: Malcolm X," scheduled to premiere at 8 p.m. EST Monday, follows the advocate's changing philosophy from a Nation of Islam black separatist to a figure seeking to build multiethnic coalitions during the tumultuous 1960s civil rights era. But it also contains never-before-seen footage of the outspoken advocate at rallies with Nation of Islam leader and eventually foe, Elijah Muhammad.