This volume is based on lectures Husserl gave at Göttingen in the summer semester of 1907. The first five lectures were separately published as The Idea of Phenomenology. The lectures describe Husserl's theory of the constitution of physical objects in detail, and are notable for the prominence of formal methods (as in the diagram above). Husserl considers the relation between visual and kinaesthetic (that is, bodily) experience in the constitution of material objects, making considerable use of the "pure theory of manifolds" introduced in the Logical Investigations. The appendices contain interesting quasi-mathematical investigations and considerations of such unusual topics as the constitution of empty space (as opposed to trees, tables, and chairs).