[Works]

Online version:

[v. 1-2] Principles of biology

[v. 3-5] Principles of sociology

[6] Education: intellectual, moral, and physical

[7] Social statistics. Man versus the state

[8] First principles

[9] Facts and comments

[v. 10-11] Principles of ethics

[v. 12-13] Principles of psychology

[v. 14-16] Essays

[17] The study of sociology

[18] Various fragments