Tredition Classics is a book series by German publisher Tredition. In addition to serving as a self-publishing platform, the company aims to “publish all the world’s classics”. Texts for these volumes are sourced from various non-profit literary projects, including Project Gutenberg. In exchange, these receive a portion of the proceeds from book sales.
The series’ cover design used since around 2012 features a (posthumous and inauthentic) portrait of Johannes Gutenberg, after a copper engraving made by Nicolas de Larmessin in the 17th century. The sans-serif caps for the series logo are from Ascender Sans. All other text is set in a single size of Ascender Serif. It’s also possible that the specific fonts in use are Liberation Sans for the former and Liberation Serif or Tinos for the latter – these are derivatives of Steve Matteson’s designs made available under open-source licenses. The versions are different in terms of character set/language support and license, but are virtually impossible to tell apart in terms of the basic design.