If you fly fish long enough, you’re bound to experience a breath-stealing moment now and then. Years ago, not long after I moved to Idaho, I remember my first such moment spent with a fly rod in hand. I’d hiked into a little creek not too far from the Wyoming border on a spectacular June afternoon, and, from the trail that led up the creek, I spied perhaps the sexiest little stretch of stream I’d ever seen. The creek meandered through a willow-choked meadow and, as it rounded a deep, undercut bank, it tailed out over a pool of deep, green water.