Recent progress in energy and momentum resolution in angle-resolvedphotoemission spectroscopy (ARPES) has made it possible to directly observe the interaction of electrons with bosonic modes responsible for the occurrence of superconductivity in high-High-Tc cuprates. This chapter explains results of recent high-resolution ARPES on hole- and electron-doped high-Tc superconductors and discusses the validity of the BCS-like framework of the superconducting mechanism, the origin of the "kink" structure in the band dispersion near the Fermi level produced through the electron-boson interaction, and the electron-hole symmetry in high-Tc cuprate superconductors.