Which books have had the biggest effect on human history will always be a hotly contested question. The New York Public Library compiled a list of the 25 books that its librarians claim have had the biggest effect on the course of history. From fiction and history, to science and religion, the following works have left their mark on the world and stood the test of time. These books continue to be checked out frequently by patrons of the New York Public Library, the second largest library system in the U.S. behind the Library of Congress, showing that they still resonate with readers despite being published decades or centuries ago. The books on this list are widely accepted by historians as works that helped to shape society, alter social practices, and capture or explain pivotal moments in human history.