This true story of the incredible horse whose smarts stumped all of Berlin and changed science reads like a fabulous STEM mystery. Clever Hans was a horse who could do math problems, tell time, read, spell, and more . . . or could he? Even after seeing Hans answer questions correctly, some people thought it must be a hoax. Scientists began to investigate. Eventually, one scientist had a groundbreaking aha! moment and realized Hans was clever in a way no one had even imagined. Turns out Hans was so smart, he changed science!