The leader is not only as important as the rod, reel, and line, but at times more important than the correct fly pattern. The leader is a device for deception as well as presentation. It deceives by being transparent, and even more by its flexibility. With the proper leader, your fly should appear unattached. It should move freely with every shift of the current or sink unhindered. Leaders are made from solid nylon, PVDF (polyvinylidene fluoride, also known as fluorocarbon), or polyethylene. Solid leaders are called monofilament leaders because they are made from a single solid filament. Leaders can also be made from tiny braided filaments. They are often classified either as braided leaders, which have a hollow core and utilize very tiny strands, or furled leaders, made from slightly bigger strands with no hollow space in the middle. Before nylon was first used for leaders, in the late 1940s, leaders were made from drawn silkworm gut. Level pieces of gut were joined with knots to form tapered leaders, which cast and straightened very well. However, gut is brittle unless soaked in water for a few hours, and it mildews and rots if not carefully dried and put away. Gut cannot be drawn with any kind of quality control in diameters less than .009-inch. Today we use nylon in diameters as fine as .003-inch, and a nylon leader is two or three times as strong as a gut leader of the same diameter.

Gut did have one advantage over nylon: it was straight. Because leaders are so long, they must be stored coiled, and nylon retains a “memory” that must be removed. You can easily remove almost all the kinks and curls from nylon leaders by carefully stretching sections between your hands or drawing them through a piece of gum rubber or leather. The heat generated by this process, along with the slow, steady pull, realigns the molecules in the nylon and eliminates most of the memory. Leaders designed to present flies properly follow tapers developed by theory and by trial and error, just as fly rods and fly lines are tapered. In fact, the whole system is one continuous taper, from the butt section of the rod to the hair-thin end of the leader. All three work together to transmit and dampen the tremendous speed and energy developed in your casting arm, to place the line, leader, and fly on the water so gently they barely ripple the surface. Leader tapers are critical to your success. I’ve seen people try fly rods with a poorly designed leader on the end and swear that the rod was no good. Leaders made from solid nylon or PVDF monofilament are tapered either by machine, in which case they are called knotless leaders, or by joining sections of “level” (untapered) material together.

special kind of knotless nylon leader is constructed with special air chambers inside so it floats better than standard solid leaders (nylon is slightly heavier than water and sinks slowly). Twenty years ago, the best leaders were the knotted variety because they could be made in compound tapers, where the diameter does not decrease at a constant rate. Don’t ask me why; the physics are too much for me. But leaders with compound tapers just cast much better. However, the process used to make knotless leaders has been greatly improved, to the point where compound tapers are now easy to create without knots. It’s hard to find a commercially made knotted leader today.

Making knotless leaders is an amazing process, where hot nylon or PVDF is extruded through nozzles that change in diameter as the material comes out, into a bath of either water or oil. The leaders are then run down a long line of machines with rollers that heat, cool, and stretch the leaders until the taper is perfect.