Final answer:
Jacob Riis and Lincoln Steffens focused on exposing social issues during the Progressive Era: Riis through photojournalism about poverty in tenements and Steffens on political corruption in city governments, both prompting public awareness and reforms.
Step-by-step explanation:
The focus of both Jacob Riis, in How the Other Half Lives, and Lincoln Steffens, in The Shame of the Cities, was to expose and draw attention to the social issues of their time. Riis used photojournalism to reveal the dire living conditions of the urban poor in New York's tenements. His work combined with his storytelling effectively highlighted the impact of poverty on immigrant families, leading to public support for reforms in tenement regulations. On the other hand, Steffens’ work concentrated on political corruption in city governments, outlining the deep-seated problems in American cities due to corrupt alliances between businesses and politicians.
These authors, part of a larger group known as the muckrakers, played critical roles in the Progressive Era reforms by informing the public and sparking the impetus for change. Their efforts exemplify how investigative journalism and visual storytelling can advocate for social reform and influence policy-making for the betterment of society.