Lukas Mathis studied Computer Science/Software Engineering and Ergonomics/Usability at ETH Zürich and works as a software engineer and user interface designer for a Swiss software company creating workflow management software. His first computer was a Performa 450, his first programming language was HyperTalk, his first electric guitar was a cheap Peavey, his first video game was a VCS 2600 and his current snowboard is from Lib Tech. He lives in a small cottage in a remote part of the Swiss Alps. You can follow him on Twitter.
Go Back and Forth Fast in Preview
If you're reading a PDF in Apple's Preview software, and you follow a bookmark or an internal link to move around within the PDF, you can quickly return to where you were by pressing the keyboard shortcut Command-[ (that's Command-Left Bracket). Or, you can choose Go > Back.
The command works iteratively, so you can go back to just the previously viewed page or if you issue the command again, to the page before that, and so on. There's also an equivalent Go > Forward (Command-]).