In 1954 they were two searing young talents from the provinces, both dreaming of Paris, glamour and glory. Saint Laurent was the charmed youth, the 'enfant terrible' inheritor of Dior’s couture crown, his frame almost too slight to bear his genius. Lagerfeld was the freelance designer with a talent for ready-to-wear. Seemingly from a background of enormous wealth and privilege, he was in fact a tireless workaholic, driven by his passion for capturing the pose of the moment.

Then the student riots of 1968 happened and staid Paris exploded like a champagne bottle left in the sun. The city embraced liberation and hedonism, furiously making up for years of post-war insecurity. It was a decade dominated by factions, intrigue, infidelities and addiction – and parties. There were costume balls, enchanted summer escapes, tea parties that turned into clubbing till dawn, and fashion was the fulcrum on which they turned.

Each designer created his own mesmerising world, a world vivid and seductive enough to pull people to them - people attracted by their power, charisma and fame. Betty Catroux, Loulou de la Falaise, Paloma Picasso, Pierre Bergé and Jacques de Bascher were all living in the mirror of fashion. The tensions of class and nationality, bohemia and luxury, youth and yearning, talent and ambition were subsumed in the creation of glamour. The two cliques could not help but become rivals.

But as the seventies turned to the eighties, heroin and Aids cast their shadow; fashion became an industry, money prevailed and the beautiful people discovered the danger of living their dreams. The Beautiful Fall is Alicia Drake’s brilliant chronicle of this dangerous, brazen, fabulous time, and the two designers who were its essence and remain its most singular survivors. Written with wit, verve and insight, full of colourful detail and vivid personalities, it is a wonderfully compulsive read.