The cruelest miles / Salisbury, Gay

Recounts how sled dogs raced over 674 miles to pick up diphtheria serum to save lives in Nome, Alaska in 1925, and they ran over rivers, up mountains, and over ice in sixty degrees below zero weather.

Tells the story of the Serum Run, a relay of dog sleds and drivers that was organized to traverse nearly seven hundred miles in temperatures far below zero in a desperate quest to acquire serum to treat a deadly outbreak of diphtheria in Nome, Alaska in 1925.