Book excerpt: Hailed as "one of the most valuable books on the relation of philosophy and science," Alfred North Whitehead's The Concept of Nature, first published in 1920, was an important contribution to the development of philosophic naturalism. Examining the fundamental problems of substance, space, and time, Whitehead assesses the impact of Einstein's theories as well as the then-recent findings of modern physics on the concept of nature. For students and teachers of natural philosophy, this is essential reading. English mathematician and philosopher ALFRED NORTH WHITEHEAD (1861-1947) contributed significantly to 20th-century logic and metaphysics. With Bertrand Russell he cowrote the landmark Principia Mathematica, and also authored An Inquiry Concerning the Principles of Natural Knowledge, The Function of Reason, and Process and Reality.