The Pratt knot is a method of tying a tie around one's neck and collar. It is also known as the Shelby knot and the Pratt-Shelby. The knot was invented by Jerry Pratt, an employee of the US Chamber of Commerce. He had been wearing his tie in the Pratt knot for some twenty years before it became popular after TV personality Don Shelby wore it on air. The New York fashion press then promptly (and mistakenly) attributed the invention of the knot to Shelby.
The Pratt knot is unique in that its starting position is 'reverse side out'. It uses less length than the Half Windsor or Windsor knots, and so is well suited to shorter ties. Unlike the Four in Hand knot, the Pratt method produces a symmetrical knot. It is of medium thickness.