This template uses the tufte-book class, one of two classes inspired by the handouts and books of Edward Tufte. The 42-page sample is the class's own book, with a front matter spread, a large margin column for sidenotes, margin figures and captions, full-width figures, and an index. It includes sample PDF figures such as a helix, Hilbert curves and a sine wave, and uses booktabs, fancyvrb and units.
Shared under the Apache License 2.0. All credit to Kevin Godby; the licence comes with the project's files.