Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file. Stop printing and start skimming. Explore the links to the left to investigate Skim and consider helping out with the project. Features: Viewing PDFs

Adding and editing notes

Highlighting important text, including one-swipe highlight modes

Making "snapshots" for easy reference

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

Focus using a reading bar

Magnification tool

Smart cropping tools

Extensive AppleScript support

Bookmarks

Saving passwords in Keychain

Export notes as text

Automatic download of remote PDFs

Support for Apple Remote Control

Interaction with LaTeX, SyncTeX, and PDFSync

Integration with BibDesk and other third party applications

Spotlight support

Highly customizable

And much more...