  This is a survey paper on spaces of automorphisms of manifolds and spaces of
manifolds in a fixed homotopy type. It describes the main theorems of
traditional surgery theory, but also the main theorems of pseudoisotopy theory,
alias concordance theory, Waldhausen style. It culminates in (an outline of) a
synthesis of these two theories, producing algebraic models, valid in a stable
range, for spaces of manifolds in a fixed homotopy type. This is inspired by
earlier work of Burghelea-Lashof and Hatcher. The algebraic models are a mix of
algebraic L-theory and algebraic K-theory.
