 First of all, there is the continuation of the work in mathematical logic from the 1920s and 1930s by people like Martin Davis—who is a student of Post and Church—and Kleene. Within that tradition, Turing’s work was of course well-known and the Turing machine was considered as the best model of computability given. Both Davis and Kleene published a book in the 1950s on these topics (Kleene 1952; Davis 1958) which soon became standard references not just for early computability theory but also for more theoretical reflections in the late 1950s and 1960s on computing.