What are the most important themes that run through both Chapters 17 and 18 in Howard Zinn's "The People's History"?

One of
the most important themes in Chapters 17 and 18 in  is that individual
action can have profound effects on social and political policy.

In chapter
17, Zinn focuses on the "black revolt of the 1950s and 1960s."  He is very direct in
how he opens the chapter.  Zinn details how specific writers and thinkers viewed the racial
divide that defined America.  The impressions of Countee Cullen, Langston Hughes were matched
with the organizing efforts of Angelo Herndon and Hosea Hudson.  In each of these perceptions,
Zinn makes clear that in order for sweeping social and political change to take place,
individual action was needed.  Zinn views the Civil Rights struggle in terms of action vs.
inaction.  Zinn's narrative focuses on inaction of government and those in the position of power
against those at the bottom rung of society who seek to create change.  He details this theme
with examples of student sit- ins...