Anticipations of the reaction of mechanical and scientific progress upon human life and thought

Recent Developments in European Thought

Ancient society

The way the world is going

Die Welt in hundert Jahren

History of Human Society

Towards the Great Peace

Tantalus

Der Weltverkehr Telegraphie und Post, Eisenbahnen und Schiffahrt, in ihrer Entwickelung dargestellt

Is civilization a disease?

Memories of the future

Anthropology