Not so long ago, California was a state that showed the world how to educate its people for productive, prosperous lives. It had a K-12 system that was a beacon for the nation. It built a public university system that was - and remains - the envy of other states and countries. This was the fertile, well-educated ground that gave birth to the high-tech revolution and the creativity that built an entertainment and information empire.

I believe California can remain that innovative and path-breaking state. But to do so it must commit to increasing the number of young people who leave school prepared for college or the world of work. That commitment to quality education can't wait for high school, or middle or even elementary school. It must begin even before children arrive at kindergarten, to make sure they all have a chance at a strong start in school. I'm talking about quality preschool for all.

Our best opportunities to maximize children's learning potential are precious and limited. In the first five years of life, their brains develop faster than at any other time. During the preschool years, we have a chance to enhance that growth by helping them to develop understanding and skills that they will build upon for the rest of their lives. For many children who are deprived of that foundation during this critical phase, the chance may be lost or seriously compromised.

Quality preschool programs capitalize on children's most explosive period of brain growth. They build not only listening and speaking skills and familiarity with letters and numbers, but the ability to pay attention to a task, to discover cause and effect, to be creative, to get along with others and to have confidence in themselves. Good preschool helps prepare them for all the learning that is expected of them starting in kindergarten. Studies show it enhances their lives for years to come.

Yet an alarming number of California children don't go to preschool. Just 47 percent of the state's 1.2 million preschool-age children (defined as those who are 3-, 4-or 5-years-old but not in kindergarten) go to preschool, according to the California Research Bureau. In some cases, that's a matter of parental choice, but in far too many it's a function of accessibility and affordability.

In neighborhoods all across the state, parents can't find space for their children in quality preschools. Federal Head Start programs don't begin to serve all eligible children; state-funded preschool programs are overenrolled in many communities.

Working families with incomes just above the eligibility threshold for these public programs ($18,400 for a family of four for Head Start, $47,820 for a family of four for state preschool) are hard pressed to afford a quality private program. In Los Angeles, 40 percent of child care centers have waiting lists for preschool children.

Latino children now make up almost half of today's preschool-age children. Yet just 37 percent of Latino children enroll in preschool. Many of those who don't enroll are struggling to catch up in school before they've even started.

In a new public school environment of heightened academic expectations, their disadvantages are that much greater. So are the risks that they will ultimately be unable to participate productively in California's economy. We ignore those risks at our peril.

A quality, part-day preschool-for-all program for 3-and 4-year-olds whose parents choose to send them will require significant public investment. But solid research suggests that the return on such an investment would make it more than worthwhile.

In authoritative studies of Michigan's Perry Preschool program, which tracked the outcomes of preschool children well into adulthood, noted economists concluded that for every dollar invested in such programs, taxpayers could save as much as $7 in avoided future costs, including remedial education, welfare and incarceration. Participating children scored higher on elementary school reading and math tests than their non-participating peers.

Other studies have echoed the Perry findings, showing higher high school graduation rates and college attendance, and more prosperous employment for adults who attended quality preschool as children. The Federal Reserve Bank of Minneapolis has calculated that public investments in quality preschool yield a real internal rate of return to the public of 12 percent. That beats the stock market.

It shouldn't come as any surprise, then, that business leaders around the country are standing up for the concept of preschool for all. The Business Roundtable and Corporate Voices for Working Families have called for it. Business Week listed free preschool education among its "25 Ideas for a Changing World."

California, however, has been slow to respond. It ranks 37th among states in enrollment rates. Georgia, meanwhile, serves 70 percent of its 4-year-olds in publicly funded preschools. New York and Florida have committed to preschool for all 4-year-olds and are searching for ways to fund it. Five years ago, the New Jersey Supreme Court ordered the state to fund quality preschool programs in 30 disadvantaged school districts; in part as a result, New Jersey serves 65 percent of all preschool age children.

My personal interest in early childhood education stems in part from my experience as a father and grandfather. In my granddaughter, now 1 1/2, I can see clearly what research has been telling us about children's early brain development.

But my interest also grew when, as chief executive officer of Hewlett Packard, I worked to improve the K-12 public school system in Silicon Valley. The inadequacy of the schools had become a competitive disadvantage for HP as we tried to recruit key employees. I realized then that a major problem was the large number of children who were entering kindergarten unprepared. The system was bogged down trying to help them catch up. Too often, it was failing.

At HP we always said we wanted people growing up in California to be educated well enough to work in California - in the well-paying manufacturing and creative jobs that make the tech sector hum. We often had to import skilled labor to fill those jobs, and that remains the case today in Silicon Valley. It's time California got serious about growing these prosperous workers at home.

That effort has to include public investment in quality preschool. There's been some encouraging momentum in that direction, with tobacco tax funds being devoted to school readiness and several counties and school districts working to expand access for children. But California needs a more comprehensive, focused program, supported by reliable funding, if it is going to reach all children whose parents want them to go to preschool.

I care about this issue because I believe it is critical to keeping California on its innovative path to prosperity. To remain a pacesetter for the nation and the world, California must lead in making sure that all its children have the chance to start strong in school. The strength of the California workforce, the health of the business climate and our quality of life depend on it.