Machado de Assis combateu o regime escravista, e não apenas em seus textos. Como cidadão e funcionário público do órgão encarregado de fiscalizar o cumprimento da Lei do Ventre Livre, conseguiu libertar centenas de vítimas da falsificação de documentos atestando terem nascido antes da aprovação da Lei.
Joaquim Maria Machado de Assis, often known as Machado de Assis, Machado, or Bruxo do Cosme Velho, (June 21, 1839, Rio de Janeiro—September 29, 1908, Rio de Janeiro) was a Brazilian novelist, poet, playwright and short story writer. He is widely regarded as the most important writer of Brazilian literature. However, he did not gain widespread popularity outside Brazil in his own lifetime. Machado's works had a great influence on Brazilian literary schools of the late 19th century and 20th century. José Saramago, Carlos Fuentes, Susan Sontag and Harold Bloom are among his admirers and Bloom calls him "the supreme black literary artist to date."