AbstractThis chapter gives an overview on block copolymer science with a special focus on bulk and thin films. Besides some important basic knowledge, recent developments in the area are covered, with a focus on morphology and mechanical properties. The chapter is confined to amorphous and crystalline block copolymers, which have a linear or star topology. Not only the blends of narrow disperse block copolymers, but also the influence of polydispersity of block copolymers on their morphological properties are discussed. The interplay of crystallization and block copolymer morphology, as well as the mechanical properties of block copolymers, and the influence of external field of the morphological alignment in thin films are portrayed.