Jacob Riis and Upton Sinclair both focused on social reform and the plight of the urban poor in their respective works, though they approached these issues from different angles and contexts.
### Jacob Riis:
- **Background**: A Danish immigrant and social reformer, Riis is best known for his book "How the Other Half Lives" (1890), which used photography and firsthand accounts to expose the harsh realities of life in New York City's tenements.
-