Our world is home to 1.8 billion young people between the ages of 10 and 24, and the youth population is growing fastest in the poorest nations. Within this generation are 600 million adolescent girls with specific needs, challenges and aspirations for the future. Never before have there been so many young people. Never again is there likely to be such potential for economic and social progress. How we meet the needs and aspirations of young people will define our common future.