Abstract operator algebras on Hilbert spaces, disk algebra, crossed product, unique covariant representation, Volterra algebra, Linear operators in \(C^*\)- or von Neumann algebras, C*-representation, completely contractive representation, Representations of topological algebras with involution, structure of norm-closed subalgebras of C*-algebras, contractive homomorphism, Noncommutative dynamical systems, Automorphisms of selfadjoint operator algebras