Science writer Sadie Dingfelder has always known that she’s a little quirky. But it’s not until she accosts a stranger in a grocery store (whom she thinks is her husband) that she realizes something is amiss. Dingfelder starts contacting neuroscientists and lands herself in scores of studies. She discovers that she has prosopagnosia (faceblindness), stereoblindness, aphantasia (an inability to create mental imagery), and a condition called severely deficient autobiographical memory. As Dingfelder begins to see herself more clearly, she discovers a vast well of hidden neurodiversity in the world at large. There are so many different flavors of human consciousness, and most of us just assume that ours is the norm. Can you visualize? Do you have an inner monologue? Are you always 100 percent sure whether you know someone or not? You may be surprised to learn that many people—including Dingfelder—can’t.