We describe various electronic and magnetic properties of the ferromagnetic 3d metals Ni, Co and Fe and related metals, including ground-state properties, Fermi surfaces and both one-electron and many-electron aspects of photoemission and optical absorption processes. Experimental de Haas-Van Alphen results for the spin-polarized Fermi surfaces and angle-resolved photoemission results for the exchange-split energy-band dispersions for Ni, Co and Fe are summarized. Single-particle energy-band descriptions of these Fermi surfaces and band dispersions, as well as various ground-state properties (lattice constant, cohesive energy, bulk modulus, magnetic moment, hyperfine field, etc.) are given in terms of the density-functional theory of Hohenberg, Kohn and Sham. In general, these properties can be understood quite well within the single-particle picture. Also discussed are troublesome questions concerning the exchange splitting, band dispersions and satellite structure of Ni. Various optical and photoemission processes for Co, Fe, Ni and Cu exhibiting many-electron phenomena are discussed, including four-level absorption edges, resonances, photoemission relaxation effects, shake-up processes and Auger processes.