This chapter describes ideas and results of controlling surface plasmon polaritons (SPPs) in nanoplasmonic waveguides. The coherent control of the quantum state of atom and molecules is based on the directed interference of the different quantum pathways of the optical excitation, which is carried out by properly defining the phases of the corresponding excitation waves. The full coherent control on the nanoscale is achieved by placing an array of nanoparticles on a SPP nanoplasmonic waveguide. A central problem of nanooptics is the commonly known impossibility to concentrate optical radiation on the nanoscale because the wavelength of light is on the microscale, many orders of magnitude too large. The 3D energy concentration occurs at the tip of a smoothly tapered metal nanoplasmonic waveguide. This causes the local field increase by three orders of magnitude in intensity and four orders in energy density.