Nanotubes have been pursued aggressively over the last three decades. Significant progress has been made in the selective growth and post-synthetic sorting of highly monodisperse carbon nanotubes, in understanding their physics, and in assembling and integrating them into high-performance devices. These discoveries have led to promising applications in areas such as high-performance CMOS, high-speed RF, thin-film transistors, flexible electronics, thermoelectrics, sensors, and optoelectronics. The rapid development of modern information technology depends on the exploitation of new and novel materials, and nanotubes have emerged as promising candidates for the post-Moore's Law era. This Special Topic on Physics and Applications of Nanotubes provides a valuable forum where researchers studying the fundamentals of nanotubes can share their most recent and novel findings.