The opening “Half Lesson” is titled: Your Brain Is Not for Thinking. It’s not? No. Your brain’s most important job is predicting your body’s energy needs before they arise so you can efficiently make worthwhile movements and survive to pass your genes to the next generation.

This short, accessible, frequently amusing and deeply subversive book exploded pretty much everything I’ve understood about the brain and how it works. That’s quite a statement given I’m a psychiatrist—my medical specialty is the brain.

For example, memories are not filed like paperwork—that’s a metaphor. They are actually recreated on demand. What! Yes. The human brain is large, but so are our bodies. Proportionally, it’s no bigger than the brains of other mammals. Nature uses the same manufacturing plan to build our brains and those of all mammals (and most likely reptiles and other vertebrates). No! Yes. The idea that natural selection has targeted the human brain to evolve to the top of the animal pyramid is wrong. We are not special or superior, simply different.

The brain is not organized into three layers: lizard (survival), limbic (emotional) and neocortex (rational). That too is a metaphor. The brain is a vast, flexible, plastic network. That’s not a metaphor but a description of the brain’s actual structure. Any one neuron can do more than one thing. Groups of neurons can configure themselves into an enormous number of different patterns. The human mind results from the brain network’s functional complexity, not from the brain’s physical size. This complexity is organized to manage the body’s energy budget, in a never-ending cost/benefit analysis that optimizes our physical survival. That agenda, which drives all our behaviors, puts “rational” in a radically different context, doesn’t it?

In seven and a half short essays, the author, a groundbreaking research neuroscientist, reveals what the brain is doing under the hood that results in what we experience as thinking, imagination, creativity, mental illness, the sense of continuity of ourselves as we age, relationships, culture, and even the meaning of life. The brain—a three-pound jelly trapped in the dark of a small bone box—creates our reality. Let that sink in.

“It’s still magic even if you know how it’s done.” Terry Pratchett