The first wave of the Millennial Generation - born between the early 1980s and 2002 - is just graduating from college and entering the work force. Employers, meantime, are bracing for some of the biggest management challenges they've ever faced: Integrating the most demanding and most protected generation in history into a workplace shaped by the driven baby-boom generation. Like them or not, millennials are America's future work force. They are actually a larger group than the boomers - about 80 million vs. 76 million.The millennials are a complex group - although they're hard-working achievers, most millennials don't excel at leadership and independent problem solving. They want the freedom and flexibility of a virtual office but they also want rules and responsibilities to be spelled out explicitly. "It's all about me," might seem to be the mantra of this demanding bunch of young people, yet they also tend to be very civic-minded and philanthropic.