What is the title of Isaac Newton's influential book published in 1687?

The title of Isaac Newton's influential book published in 1687 is "Philosophiæ Naturalis Principia Mathematica." This work, often simply referred to as the "Principia," laid the groundwork for classical mechanics and introduced key concepts such as the laws of motion and universal gravitation.

Newton's "Principia" is significant because it was one of the first texts to apply mathematical principles to physical phenomena, providing a systematic framework for understanding the forces acting upon objects and how they move through space and time. The book revolutionized the field of physics and greatly influenced the scientific revolution, setting the stage for future scientific inquiry.

This title differentiates itself from the other options provided. "Theory of Relativity" refers to Albert Einstein’s work on the relationship between space and time, while "On the Origin of Species" is Charles Darwin’s foundational text on evolutionary biology. "Principia Mathematica," while a title used to refer to Newton’s work, is not the full and correct title that captures the essence of the work in the context of its publishing. Thus, "Philosophiæ Naturalis Principia Mathematica" is correctly recognized as the authoritative title that signifies Newton's monumental contributions to science.