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. Skim requires Mac OS X 10.6 or higher.
- 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
- 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...
This is literally the best pdf reader/annotator on macOS. Preview is simple in functionality, which is also good, but if you want just a little bit more functions, Skim is the one to go!
Perfect for reading and annotating scientific PDF articles!
For anyone wanting a vertically split PDF view, it is quite easy if you are willing to download and compile the source files. Open the MainWindow.xib in Xcode and select the "Pdf Split View". On the right-hand side, select "Show the attributes inspector" and under "Split View" change the value for "Arrange" from "Top to bottom" to "Left to right". Compile and the resulting app will show two PDFs side-by-side when you select "View | Show split PDF".
The best. I just wish the auto-hide TOC feature that was available in versions prior to 1.4.13 is supported in all OSX versions as opposed to just 10.6 (as per ver.1.4.22 via SKHideClosedFullScreenSidePanels) since v.1.4.12 just refuses to work on Sierra and I'm stuck with switching command+shift+T instead of simply hovering to the left side to show the TOC panel. MacOS Sierra slow scrolling bug is already ironed out in the upcoming version. For those who can't wait, choosing single page view mode then single page continuous after opening the pdf file *should* fix the problem (tested and works on v1.4.13 or newer)