Dr. Andrew’s “The six keys to the normal occlusion” is a must-read article. He invented the “Straight wire appliance” concept. Thanks to his prescription brackets, we don’t have to bend wires so much in clinic. Before his invention, orthodontist used 0-0 prescription brackets and had to bend to follow the tooth anatomy (in-and out bend, canine eminence, etc).
I like Dr. Alhamlan’s revision in the below. It is easier to read and understand.