The International Symposium on Nanonetwork Materials: Fullerenes, Nanotubes, and Related Systems was held in January 2001 in Kamakura to exchange the newest research results and to discuss the current status and future prospects of carbon nanotubes, fullerenes, and related network meterials which are now the subjects of the highest interest and the most intensive research in nanoscience and nanotechnology. Due to the high importance of these materials in various fields, such as physics, chemistry, and many engineering fields, scientists from all over the world attended this symposium. These proceedings cover the synthesis, electronic properties, and mechanical properties of fullerenes, nanotubes, and related covalent-bond network materials.