v. 1. Einstein's Zurich notebook: introduction and source / Michel Janssen ... [et al.] -- v. 2. Einstein's Zurich notebook: commentary and essays / Michel Janssen ... [et al.] -- v. 3. Gravitation in the twilight of classical physics: between mechanics, field theory, and astronomy / edited by Jürgen Renn and Matthias Schemmel -- v. 4. Gravitation in the twilight of classical physics: the promise of mathematics / edited by Jürgen Renn and Matthias Schemmel