Book excerpt: The On The Fly Guide to the Northern Rockies distills a lifetime of exploration and experience into a guide that will help you successfully plan a trip to the prime waters of Idaho, Montana and Wyoming. Chuck Robbins has picked his favorite rivers and lakes; shares his wealth of insider information on how to fish these premier waters and the best time to fish them; his favorite fly for each water; along with his personal recommendations for great food and interesting places to stay; and many other tips. Book jacket.