“I suffered evils,” said the Black photographer Gordon Parks, who died in 2006, “but without allowing them to rob me of the freedom to expand.” Expand he did, leaving behind an exceptional body of work that documents American race relations from the 1940s to the new millennium. Parks was born in Fort Scott, Kansas, in a segregated community, and the experience fueled his fight for social justice. In Part One of this exhibition, two stories are told through two series of photographs: “Segregation in the South” (1956) and “Black Muslims” (1963). —E.C.