A New View
You can display Finder windows in three ways. Two options — list view and icon view — are the same as in OS 9. But in place of OS 9’s button view is a new column view, borrowed from NeXTstep. Column view lets you navigate a disk’s folder structure horizontally. (For example, you click on a folder in the left-hand column to peruse its content in the right-hand column.)
Look before You Leap
In column view, when you select an application or file icon, its preview image appears in the Finder-window column to the right.