In his 2008 best-selling book, Outliers: The Story of Success, Malcom Gladwell, using the Beatles as a case study, introduced his readers to the “10,000 hour rule,” explaining the Beatles’ musical success as a product of the long hours the group had to play during their apprenticeship in Hamburg in the early 1960s. Unnoticed by Gladwell, Hamburg played a decidedly important role in the Beatles’ story for another reason: they met Astrid Kirchherr, who became a member of the Beatles’ inner circle in 1960. When she asked them if she could take their photographs, she had no idea that the pictures of them in iconic poses around Hamburg would become an important part of the visual record of the most famous rock band in history. Astrid contributed to the Beatles’ sense of style and fashion, most famously their famous mop-top hairstyle, but Pauline Sutcliffe – whose brother Stuart played bass for the Beatles at the time and married Astrid before his early death – thought Astrid had influenced the Beatles’ music as well. Astrid was a revelation for the Beatles; at the age of 22, she possessed both an air of mystery and an aura of sophistication that made her as much a muse as a friend.