It started in February 1933 when a Wisconsin farmer brought a dead cow and a bucket of cow's blood to the lab of a young University of Wisconsin biochemist named Karl Paul Link. The farmer's cows were dying mysteriously. Their blood would not clot.

Over the next two decades, Link and his team solved the mystery, and in doing so, developed a powerful rodenticide and life-saving human anticoagulant called warfarin, which was famously administered to President Dwight Eisenhower after a heart attack.

At the center of the story is Karl Paul Link - brilliant, outspoken, controversial, humorous - a colorful anti-authoritarian who twice received the Lasker Award, an honor for medical investigators second only to the Nobel Prize.

This biography traces Link's life from humble Indiana beginnings to the labs and lecture halls where he made his name - and 20th-century medical history.