Manipulating atoms and photons is one of the key issues of modern quantum optics. Various ideas have been proposed so far in this context. Examples would include laser cooling and trapping, electromagnetically induced transparency, and cavity-QED. In this talk, we propose a novel method to manipulate atoms and photons using subwavelength-diameter silica-fibers, â€œoptical nanofibersâ€. We show theoretically and experimentally how optical nanofibers can open new perspectives for manipulating atoms and photons, such as modification of spontaneous emission, super-radiance, etc. We explore the nanofiber/atom interaction using laser-cooled Cs-atoms. We demonstrate that photons from small number of atoms, average number of which is less than one, can readily be observed through nanofiber with good S/N ratio. We show also that the optical nanofiber can work as a very effective tool for exploring van der Waals interactions between atoms and fiber surface. We show furthermore that single atoms around the nanofiber reveal peculiar spectral features different from those for free atoms atom, which imply a possibility to trap single atoms on the nanofiber surface without any external field.