DOG DRIVEN by Terry Lynn Johnson

Fourteen year old McKenna has been dogsledding since she could walk. Her mother was a champion racer, and McKenna is following in her footsteps. The Great Superior Mail Run race will be the longest race McKenna has ever entered, but there's another reason she wants to win this one. Emma, McKenna's little sister, is providing the motivation for McKenna to enter and win this race. Emma was diagnosed with Stargardt disease, a degenerative condition that destroys the retina eventually resulting in blindness. 

The Great Superior Mail Run race pays tribute to the mail couriers who used to deliver mail by dogsled back in the 1800s. The race will follow one of the routes used by the original mail couriers, and as an additional challenge, each of the modern-day dogsled racers must carry a bag of letters across the finish line. The letters McKenna will be carrying have been written by the students in Emma's class. Emma's letter is particularly special as she wrote it to the Foundation for Fighting Blindness asking for research to fight Stargardt disease.

As McKenna prepares for the race, she hides a secret. For some time now, her own vision has been deteriorating. Recent changes in her sight have her convinced that she also has Stargardt disease. Winning the race could help her sister, and it could also show her parents that she can be independent even though her vision is compromised. But, it is soon clear to McKenna that running her dogs and keeping her condition a secret may be more of a challenge than she bargained for.

DOG DRIVEN by Terry Lynn Johnson has just the right combination of action, emotion, and history to appeal to middle grade readers and up. This Junior Library Guild Selection book is a fast-paced, must-read. I hope to read more about McKenna Barney and her future adventures.