He was a man of seeming contradictions. Born to great wealth, Bobby Kennedy made common cause with the least fortunate. Initially viewed as ruthless over time he became deeply concerned with the plight of others — and he struggled to find realistic political solutions to their problems. He loved a crusade, and in his early years in public life, he opposed communism, corrupt labor-union leaders and organized crime. Later, he found larger, more complex targets to address: racism, poverty, institutional indifference. Most important, he challenged all of us to join him, not simply in imagining a better world for all, but in doing the difficult, everyday work of making those visions reality.

Fifty years after Bobby Kennedy's assassination, celebrate his legacy with this special edition TIME Robert F. Kennedy.