Six years after the discovery of high-T(c) superconductivity in the system Bi-Sr-Ca-Cu-O, the superconducting compounds have been identified, and their structures, crystal chemistry, phase equilibria, and properties investigated extensively. In this article recent results of studies of the crystal chemistry and phase equilibria are presented and discussed with respect to further studies in this field and in order to give materials scientists, chemists, and physicists insight into the phase equilibria and crystal chemistry of these challenging materials.