Linda Newbery 
The Brockenspectre 

Tomas wants to be like his father – strong, brave and fearless. Pappi is a mountain guide, often away from home. He has taught Tomas to love the mountains, but also to fear their dangers – the winds and blizzards, the treacherous paths, the giddying slopes.
Above all, Tomas fears the Brockenspectre – a huge, shadowy creature that lives alone in the heights, waiting for unwary climbers. Its looming figure haunts his thoughts and his dreams.
When Pappi goes out one day and fails to return, Tomas knows it’s up to him to search – up on the high mountain passes, where dangers await.
Will Tomas find his father . . . or will the Brockenspectre find him?