"Supplement to the Collection of Messages and Messages of the Presidents: William McKinley" is a nonfiction publication based on the messages, speeches, and official documents of American President William McKinley. This book allows the reader to immerse himself in the history of the United States in the first decade of the 20th century and learn more about the political decisions that were important for the development of the country at that time. Through the prism of unique materials, this book examines the presidency of William McKinley from a new perspective, revealing his role in the events of his time. For those interested in American history and wishing to better understand the period of William McKinley's presidency, this book will be an important source of information.