“If stem cells divide equally, so both daughter cells look more or less the same, each one becomes another stem cell. If the split is unequal, neurons form prematurely.”

American writer

Sam Kean is an American writer known for books that tell the story of scientific discoveries in a narrative style. He was born in Sioux Falls, South Dakota, and lives in Washington, D.C. He has written for The New York Times Magazine, Mental Floss, Slate, Psychology Today, and The New Scientist. He has also published eight books, and they have been reviewed positively by The Wall Street Journal, Library Journal, and The New York Times.