From Aqua to Catalina: The evolution of Mac OS X

Mac OS X has been through a lot in 20-plus years. As someone who was sitting in the front row at Macworld Expo when then-CEO Gil Amelio brought Steve Jobs on stage to celebrate Apple’s purchase of NeXT, it feels like I’ve been a witness to the whole story.

The macOS we use today is the result of iteration—sometimes rapid, sometimes painfully slow—over 16 major OS releases during those 20 years. Here are the highlights.