Track 1 - The 109 project The 109 series 10 ten to the ninth power, one billion is the name of this series of monographs. Each issue will explore the Billions Club from a di erent perspective: a genre, a decade, an artist, a theme. Every volume is an independent, complete analysis, packed with data and stories. Not a blog, not a transcribed podcast: a publication with its own form and its own voice. The name is no accident. $10^9$ is the scienti c notation for a billion precise, universal, recognizable in any language. It is also a number that, when spoken aloud, sounds almost like a verse: ten to the ninth. There is something musical in that progression. This is the rst issue. It talks about boy bands and girl bands groups that critics have often treated as disposable products, but which tell a very di erent story inside the Billions Club. How to read this volume You don't need to be a music expert. You don't need to have listened to every song mentioned. You only need to be curious. You just need the desire to understand how popular music works, what it says about us, and why certain tracks cross decades and continue to be listened to by millions of people every single day. "Data is the starting point, not the destination. Numbers raise questions. Stories try to answer them." 3