For fifty-seven years, the grizzly bears of Glacier National Park had never killed a human being.

That ended on the night of August 12, 1967.

In the dark hours before dawn, in two separate locations miles apart, two grizzly bears attacked two young women sleeping at backcountry campsites. Julie Helgeson, nineteen, a seasonal park employee from Minnesota, was dragged from her sleeping bag near Granite Park Chalet and mauled while her companion survived. Michele Koons, also nineteen, was attacked at Trout Lake. She couldn't escape. Her sleeping bag zipper was stuck. The bear carried her into the night.

It was no coincidence that this happened in 1967. For years, the Park Service had allowed garbage to accumulate near campsites and tourist areas. Bears had grown accustomed to human food and lost their wariness of people. The park service knew. The warnings went unheeded. Jack Olsen documented how years of mismanagement and institutional complacency created the conditions for tragedy and made that terrible night all but inevitable.

The attacks were a lightning bolt to the entire National Park Service. Every rule that exists today about food storage, bear canisters, and campsite management traces its origins to that August night. Night of the Grizzlies is the book that changed how America thinks about sharing wild land with wild animals.

Originally published in 1969 and never out of print, Night of the Grizzlies has introduced generations of readers to one of the most haunting true stories ever told about the American wilderness.

In 2024, New York Times bestselling author Ryan Holiday named it the second-best book he read all year, writing: "your dread increases as the book goes on, as each warning is ignored, each chance to prevent the tragedy is missed, and each page brings you closer to what you know will be the gruesome, violent, and now unavoidable action. This book deserves to be much more well-known."

He was right. This is the book that started it all.