Vermont is drying up. The normally lush, green countryside is in the grip of the worst drought in years: stunted cornstalks rasp in the hot July breeze, parched vegetable gardens wither and die, the Chittenden River shrinks to a trickle, and the drilling trucks are booked solid as one by one the wells give out. Patience Avery, known nationwide as a gifted "water witch," is having a busy summer, too. Using the tools of the dowser's trade -- divining sticks, metal rods, bobbers, and pendulums -- she can locate, among other things, aquifers deep within the earth. In the midst of this crisis,...