 Set-theoretic mathematics continued its development into the powerful axiomatic and structural approach that was to dominate much of the 20th century. To give just a couple of examples, Hilbert’s early axiomatic work (e.g., in his arch-famous Foundations of Geometry) was deeply set-theoretic; Ernst Steinitz published in 1910 his research on abstract field theory, making essential use of the Axiom of Choice; and around the same time the study of function spaces began with work by Hilbert, Maurice Fréchet, and others. During the 1920s and 30s, the first specialized mathematics journal, Fundamenta Mathematicae, was devoted to set theory as then understood (centrally including topology and function theory). In those decades structural algebra came of age, abstract topology was gradually becoming an independent branch of study, and the study of set theory initiated its metatheoretic turn.