Once the stuff of sci-fi fantasies, artificial intelligence is taking over the world.

It completes half-written words in your texts. It answers questions through your smartphone or smart speaker. It plots the quickest route from here to there. It recognizes familiar faces at your door, curates your social feed, fills your playlist. It slaps ads for those cool boots you considered buying on every webpage you look at.

And it’s only going to become more sophisticated. Auto makers are conceiving self-driving vehicles to ferry people to their destinations, then park or carry other passengers until pickup time. Lights and thermostats can connect to your smartphone’s location sensors, so your home can go to sleep when you depart and wake up when you return. Factory robots are sorting goods into customer orders that might be carried to your doorstep by autonomous quadcopters.

AI isn’t the next big thing—it’s here now, and it shows no sign of letting up. Here’s an introduction to the technology you soon may come to regard as your new helper, teacher, colleague, neighbor, or overlord—I mean best friend.