Let’s meet the major players on the generational stage, beginning with those who emerged first.

• Matures: There are 57.8 million Matures, people born from 1912 through 1945. Matures made up about 20.5 percent of the population, according to 2000 Census figures. Some subdivide the Matures into the GI generation (born 1912-1921), the children of the Depression (born 1922-1927) and the Silents (born 1928-1945). The wealthiest generation, they have an immense economic impact: an estimated $20 trillion.

• Boomers: They were the biggest generation the United States had ever seen. Numbering 82.8 million people born from 1946 through 1965, boomers represented 29.4 percent of the U.S. population in 2000, with estimated annual spending of $900 billion.

• Generation X: A significantly smaller group, with a population of 58.9 million in 2000, Gen Xers were born from 1966 through 1979. They make up 20.9 percent of the population and spend about $125 billion per year.

• Generation Y, also known as Echo Boomers and Millennials: Members of Gen Y are the children of boomers and Gen Xers. They were born from 1980 through 1999. Numbering about 80.5 million, or 28.6 percent of the population in 2000, they already represent considerable purchasing power: an estimated $105 billion per year. As they come into their own, their impact will rival that of the boomers.