Evidence!

The incredible true story of the doctor who traced London's cholera outbreak to a single water pump, and went on to save countless lives through his groundbreaking research!

Dr. John Snow is one of the most influential doctors and researchers in Western medicine, but before he rose to fame, he was just a simple community doctor who wanted to solve a mystery.

In 19th century London, the spread of cholera was as unstoppable as it was deadly. Dr. Snow was determined to stop it, but he had a problem: His best theory of how the disease was spread flew in the face of popular opinion. He needed evidence, and he needed to find it fast, before more lives were lost.

Taking on the role of detective as well as doctor, Dr. Snow knocked on doors, asked questions and mapped out the data he'd collected. What he discovered would come to define the way we think about public health to this day.

This compelling nonfiction picture book is a timely reminder of the power of science to save lives.

Deborah Hopkinson is the author of many highly acclaimed picture books, including A Letter to My Teacher, which received two starred reviews, and the modern classic Sweet Clara and the Freedom Quilt, which the New York Times called "inspiring." Her other books include Sky Boys: How They Built the Empire State Building, a Boston Globe-Horn Book Honor Book; and Abe Lincoln Crosses a Creek: A Tall, Thin Tale, an ALA-ALSC Notable Children's Book. She lives in Oregon with her family.

Nik Henderson was raised in Strafford, Missouri, where he still lives, and studied illustration at the Savannah College of Art and Design in Savannah, Georgia. He is the illustrator of Trucks on Trucks by Sorche Fairbanks, which Booklist praised for its "eye-catching" art. Evidence! is his second picture book.