OAPEN works with to provide an open annotation layer on top of the books and chapters in the OAPEN Library. enables sentence-level note taking or critique and allows readers to choose whether these notes should be made public or remain available for private use only. The tool enables researchers to take and organize personal notes, to collaborate with others, and to engage in public discussions on documents across the web.

Here is how it works:

  • On the landing page of a book or chapter, select the button “PDF viewer” to open the annotation tool;
  • Sign up or log in;
  • Use the icons on the right side of the frame to highlight a selection of text and add an annotation;
  • Select if the note should be for private use or made public.

Annotation is a service provided by as part of the OPERAS HIRMEOS-project, to enrich open access digital monographs published on five digital platforms.