Michael Tonello didn't grow up wearing Hermès, the venerable French label founded in 1837 by Thierry Hermès as a saddlery. He never coveted Hermès ties or scarves, hallmarks of the upper crust. And the American hairstylist certainly never gave a rat's arse about the world-famous Birkin bag, the clunky, rectangular satchel so elusive that billionaires can't always get their hands on them. For the longest time, Tonello didn't even know what a Birkin was. He just wanted enough dough to live in dreamy Barcelona. But after falling into the resale business, he haphazardly discovered the formula for procuring Birkins. And...