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