Find out why hair stylist Sam McKnight is adored by supermodels Gigi Hadid, Cara Delevingne, Karlie Kloss and Doutzen Kroes why Karl Lagerfeld says "Sam is the best hair stylist in the world". In 2016 Sam McKnight celebrates 40 years working in fashion with the launch of his book "Hair by Sam McKnight" and exhibit at Somerset House in London.