Skim is a PDF reader and note-taker for Mac computers. It is designed to help you read and annotate scientific papers in PDF, but it is also great for viewing any PDF file.
Main features:
- Adding and editing notes.
- Navigation using table of contents or thumbnails, with visual history.
- View all your notes and highlights.
- Convenient reading in full screen.
- Giving powerful presentations, with built-in transitions.
- Handy preview of internal links.