His doctoral dissertation is entitled Development and Application of Refined Path Monte Carlo Methods.
For the academic year 2010–2011 at the University of Bern, he held an interim chair (Lehrstuhlvertretung) for the history and philosophy of science.
[4] With Jürgen Renn, Sauer investigated and published Einstein's 1912 Zurich notebook, which is important for the history of the emergence of GR.
Renn and Sauer explicated the role that Rudi W. Mandl played in urging Einstein to publish on gravitational lensing.
[14][15] In 2016 Sauer gave the historical lecture „Ich bewundere die Eleganz Ihrer Rechnungsweise“ - Einstein und die Mathematik (I admire the elegance of your calculations — Einstein and mathematics), which was part of the events accompanying the Euler Lecture.