The book is a detailed examination of the living conditions of the poor in New York City in the late 19th century. It provides a vivid and often shocking account of life in the slums, tenements and sweatshops of the city, based on the author's own investigative journalism. The book had a significant impact on public opinion and led to changes in housing laws and social policy.

"América Hispánica: (1492-1898)" is a comprehensive historical analysis of Hispanic America from the time of Christopher Columbus's first voyage in 1492 to the end of Spanish rule in 1898. The author meticulously details the exploration, conquest, and colonization of the Americas, the establishment of Spanish rule, the socio-economic structures, and the eventual struggles for independence. The book offers a deep understanding of the complex and often turbulent history of Hispanic America during this period.

"The Battle with the Slum" is a historical documentation of the living conditions in the slums of New York City during the late 19th and early 20th century. The author, a social reformer and journalist, provides a detailed account of the overcrowded and unsanitary conditions that the city's poor were subjected to. The book also highlights the efforts of the government and philanthropists to improve these conditions and eradicate the slums, emphasizing the importance of housing reform and social welfare in urban development.

"Letters to a Young Novelist" is a collection of fictional letters addressed to an aspiring writer, wherein the seasoned author shares insights and reflections on the craft of writing. Through these letters, the author delves into the complexities of narrative techniques, character development, and the interplay between personal experience and fictional creation. The book serves as a mentorship from afar, offering both practical advice and philosophical musings on the art of storytelling, aiming to inspire and guide the next generation of writers in their creative endeavors.