Back in 1991 Sumio Iijima ?rst saw images of multi-walled carbon nanotubes in the TEM. Two years later, he and Donald Bethune synthesized the ?rst single-walled nanotubes (SWNTs). Since then, we have seen tremendous - vances in both the methods for nanotube synthesis and in the understanding of their properties. Currently, centimeter-long SWNTs can be readily grown at selected positions on a solid substrate, and large quantities of nanotubes can be produced for industrial applications. Signi?cant progress has been made in producing nearly homogeneous samples of nanotubes of only a few diameters/chiralities. It is expected that the development of techniques for the synthesis of a single type of nanotube is not far away. At the same time, physical and chemical procedures for the separation of nanotube mixtures are being demonstrated. In addition to pure nanotubes, derivatized n- otubes with attached chemical or biochemical groups are being prepared. Nanotubes acting as containers for atoms, molecules (such as the "peapods") and chemical reactions are attracting signi?cant attention. In parallel with the synthetic e?ort there has been a race to decipher the properties of these materials. It is now clear that nanotubes possess unique mechanical, electrical, thermal and optical properties. Scientists and en- neers around the world are exploring a wide range of technological appli- tionsthatmakeuseoftheseproperties.