Studies of the structural polymorphism exhibited by block copolymers in the presence of selective solvents are relatively recent, but very promising in terms of fundamental understanding and practical applications. Highlighting recent advances, this review progresses from 'dry' ordered copolymers to solvated ordered (gel-like) copolymers and lastly to solvated disordered (but focally organized) copolymers. Organic- and aqueous-solvent-based systems are concurrently examined to cross-fertilize polymer and colloid science.