"The age of A.I. has begun." On Tuesday, Bill Gates sent this mostly hopeful message out to the world through his Gates Notes blog and email list. Of course, artificial intelligence in general, and public-facing A.I. apps such as ChatGPT, Bard, and the new A.I.-powered Bing, have gotten plenty of headlines recently. But, Gates says, much bigger changes are coming. "The whole experience was stunning," he writes. "I knew I had just seen the most important advance in technology since the graphical user interface." And so, in Gates-like fashion, he immediately began imagining how A.I. could rewrite the future. Here are some of the changes he foresees, and what you should do to prepare.