Thomas Henry Huxley is best known for his staunch and vociferous defense of the works and reputation of his colleague and friend, Charles Darwin. However, Huxley was probably the most distinguished and accomplished comparative anatomist of the 19th century. Among his most influential conclusions was the fundamental association of birds and dinosaurs: a theory that has gained momentum again in recent decades. This book includes six lectures by Thomas Henry Huxley that clearly demonstrate his importance to scientific thought in his own right. This edition of Huxley's "An Introduction to the Classification of Animals" is the second entry in the Foundations of Biological Thought series published by Briar Bird Press. The series presents the pivotal works of 19th century naturalists remastered for modern readers. Meticulously edited, these volumes preserve the author's intent in design and content, including the manuscript's original annotations and amendments. In addition, revised page references and editor's notes are included throughout to retain the utility of the works for both study and reference.