Catherine, Princess of Wales is launching a campaign on early years development.
The 41-year-old royal says that not enough attention is paid to the "critical importance of our early childhood" and how profoundly a child's first five years can shape their life.
In an open letter, the princess - who has children Prince George, nine, Princess Charlotte, seven, and Prince Louis, four, with her husband Prince William - said: "We all need to know the critical importance of our early childhood. They really are years like no others in our lives.
"I urge everybody reading this to take the opportunity to learn more about this incredible time of life, to think back to your own childhood and how it shaped you, and most importantly, to ask yourselves what you can do to make the world a more supportive and loving place for our children. Because healthy, happy children share a healthy, happy future."
The campaign, which will begin this week, is the latest stage in the princess's efforts to raise awareness of the importance of early childhood development.
In a previous report for her Royal Foundation Centre for Early Childhood, she warned how the roots of adult problems - such as mental health and addiction issues - stretch back to the earliest years of life.
Neil Leitch, chief executive of the Early Years Alliance, has welcomed the princess's efforts.
He said: "For far too long, the early years has been deprioritised, disregarded and ignored when it comes to sector funding, despite a wealth of research showing that the first five years of a child's life are absolutely critical in shaping their long-term learning and development.
"We hope that the princess's dedication to highlighting the importance of early childhood will prompt the government to sit up, take action and realise that education doesn't just begin when a child reaches the school gates."