Thomas H. Huxley, an English biologist and essayist, was an advocate of the theory of evolution and a self-proclaimed agnostic. A talented writer, his essays helped to popularize science in the 19th century, and he is credited with the quote, "Try to learn something about everything and everything about something." In The Advance of Science in the Last Half Century, he presents a summary of the major developments in Physics, Chemistry and Biology during the period 1839-1889 and their impact on society, within the historical context of philosophical thought and scientific inquiry going back to Aristotle. Huxley's clear and readable prose makes this subject equally enjoyable for both the student of scientific history and the casual listener alike.