The aluminum PowerBook G4 marked the point when Apple’s professional notebooks took on the sleek aluminum design language that would shape the company’s laptops for years afterward, beginning with the 12-inch and 17-inch models in January 2003 and the 15-inch aluminum version later that September. It also sits at an important transition in Apple laptop history: a refined, Mac OS X–era PowerBook that helped bridge the gap between the earlier titanium models and the later MacBook Pro generation.

• EveryMac