Preface (Martin Davis).-

I Introduction (Sommaruga, Strahm).-

II Turing and the history of computability theory .-

1. Conceptual Confluence in 1936: Post & Turing, Martin Davis and Wilfried Sieg.-
2. Algorithms: From Al-Khwarizmi to Turing and Beyond, Wolfgang Thomas.-
3. The Stored-Program Universal Computer: Did Zuse Anticipate Turing and von Neumann? Jack Copeland and Giovanni Sommaruga.-

III Generalizing Turing computability theory.-

1. Theses for Computation and Recursion on Concrete and Abstract Structures, Solomon Feferman.-
2. Generalizing Computability Theory to Abstract Algebras, John V. Tucker and Jeffrey Zucker.-
3. Discrete Transfinite Computation, Philip Welch.-
4. Semantics-to-Syntax Analyses of Algorithms, Yuri Gurevich.-
5. The Information Content of Typical Reals, George Barmpalias and Andy Lewis-Pye.-
6. Proof-theoretic Analysis by Iterated Reflection, Lev Beklemishev.-

IV Philosophical reflections.-