Fly fishing is a technique in which fish are caught by using artificial flies that are cast with a fly rod and a fly line. The fly line is a large diameter line that is heavy enough to send the fly to the target. The fly fishing methods are nest described as using the weight of the line to carry the hook through the air, rather than using the weight of the lure or sinker at the end of the monofilament line to cast the hook or lure. Artificial flies are of several types; imitating insects, bait fish or crustaceans. Flies can either float or sink, and range in size from a fraction of and inch (a few millimeters) to several inches (32+ cm) long.

Artificial flies are made by fastening hair, fur, feathers, or other materials, both natural and synthetic, onto a hook using a wound spool of thread and cement. The first flies were tied with natural materials, but synthetic materials are now very common. The flies are tied in sizes, colors and patterns to match local terrestrial and aquatic insects, bait fish, or other prey attractive to the target fish species.

Collector flies are typically ones that have not been used for fishing but have been preserved and kept in their original finished condition.  In some cases a collector fly might be mounted and framed with the makers signature and trademark. Fly fishing memorabilia in the form of finished flies, fly boxes and fly collections are attractive additions to the home decor and in many cases can be very valuable collector's items.