A loop knot can be used to attach most fishing lures and all hooks and flies. A loop allows greater action of the lure or fly and always ensures the line will pull straight down the shaft. With knots that cinch tight agains the eye of the hook, the may move off to one side causing it not to pull straight.
There are many different types of loop knots but I have found this one to be the easiest to tie and have never had it come loose. I use it for 2 pound fish as well as fish over 100 pounds here in Florida.