Photoemission spectroscopy is one of the powerful tools to understand electrons that ultimately determine the electronic, magnetic, chemical, mechanical, optical, thermal, and structural properties of solid materials. In this talk, I will introduce brief history of photoemission spectroscopy and several types of photoemission spectroscopy technique. More specifically, angle-resolved photoemission spectroscopy (ARPES) shows how electrons are bound within a crystal as a function of energy and momentum, revealing fundamental information ranging from basic electron band structure to complicated many-body physics. Recent development of ARPES technique made it possible to study (1) hot electrons with momentum resolution utilizing laser, so called time-resolved ARPES, and (2) another quantum number, spin, with spin-resolved ARPES. These new techniques reveal electron dynamics in ultra-fast time scale and spin information as well as intriguing spin-light interactions, respectively, which are expected to play important roles in understanding new correlated electron phases.