Surface diffusion of atoms, which are able to travel micron lengths over the surface of nanotubes (NTs) and underlying substrates in reaching the open edges of layers, is shown to be a key transport-kinetic mechanism involved in NT growth. It provides a set of basic effects: intrinsic growth anisotropy, open-end stability and preservation of the hollow structure of NTs, edge stability against pentagon defect formation causing NT closure, morphological stabilization of growth against growth perturbations of the edge and formation of "bamboo"-like structures. (C) 2002 Elsevier Science B.V. All rights reserved.