- The Origin of Music - "The hypothesis that music had its origin in the amatory sounds made by the male to charm the female, has the support of the popular idea that the singing of birds constitutes a kind of courtship-an idea adopted by Mr. Darwin when he says that "the male pours forth his full volume of song, in rivalry with other males, for the sake of captivating the female...".

-Political Organization in General -Political Integration -Political Differentiation -Political Forms and Forces -Political Heads - Chiefs, Kings, etc... -Compound Political Heads -Consultative Bodies -Representative Bodies -The Militant Type of Society

- Climate and its influences on People - "Life in general is possible only between certain limits of temperature; and life of the higher kinds is possible only within a comparatively narrow range of temperature, maintained artificially if not naturally. Hence it results that social life, presupposing as it does not only human life, but that life vegetal and animal on which human life depends, is restricted by certain extremes of cold and heat..."

Immanuel Kant and the Critical Philosophy.

The Principles of Psychology - Vol. I by Herbert Spencer. This book is a reproduction of the original book published in 1871 and may have some imperfections such as marks or hand-written notes.

The Factors of Organic Evolution by Herbert Spencer. This book is a reproduction of the original book published in 1887 and may have some imperfections such as marks or hand-written notes.