Winter is the season that most tests our mettle. There are the obvious challenges of the weather-freezing rain, wind chill, deep snow, dangerous ice-but also the psychological burdens of waiting for spring and the enduring often false starts that accompany its eventual return. On the surface, perhaps, winter might seem an odd season for a nature book, but there is plenty of beauty and life in the woods if only we know where to look. The stark, white...